Lots of companies succeed in selling products or delivering services, but very few make an indelible mark on the world.

A few companies, however, have managed to invent products that fundamentally change how we live. These three have done that before, and are poised to do it again.

Facebook (NASDAQ:FB) has already changed how mankind interacts with its social network. Apple (NASDAQ:AAPL) has done the same by creating the iPhone -- a portable computer that paved the way for the global availability of smartphones. And Alphabet's (NASDAQ:GOOG) (NASDAQ:GOOGL) Google search engine has changed how people access information by bringing order to the Internet and putting pretty much all of mankind's knowledge just a few keystrokes away.

These technology giants have already changed the world, and if their latest initiatives succeed, they may do so again.

Jamal Carnette (Facebook's Oculus): In technology, it's always hard to predict "the next big thing," and even harder to accurately predict life-changing products and services. That said, perhaps the technology with the best chance to attain that laudable designation is Facebook's Oculus virtual-reality headsets.

The Oculus headset Source: Facebook

Right now, the headset's functionality tends to center on gaming, but that's only scratching the surface in terms of potential market applications. Future users can integrate intense training sessions in highly skilled, critical fields like medical surgery, flight training, and military preparedness into its immersive virtual-reality experience in order to save money, increase skills, and limit unnecessary loss of life.

After buying the company in 2014 for $2 billion, the purchase is about to bear fruit. Oculus Rift ships in early 2016 but it won't be cheap. The headset itself is expected to cost around $350, in addition to a powerful PC that will be needed to deliver the graphics. Oculus CEO Brendan Iribe has said a full experience could cost upwards of $1,500, at least for users that don't already have a high-end computer. Of course, this cost should come down over time, just like all new technologies, but early adoption is always pricey.

Still, the company has multiple content partnerships in place as a testament to how many expect the format to take off. And while these are great partnerships, they're certainly not life-changing in the traditional sense.

However, I'll be looking forward to the second-wave of VR applications that should take off once the format is adopted. In the end, VR could be the most disruptive force in education and training since the personal computer.

Daniel Kline (the Apple car): Apple has not even admitted that it's making a car, but a number of signs point toward it. The company has been hiring executives and engineers with auto-industry experience. According to The Wall Street Journal, the company has named the car effort Project Titan, and has targeted 2019 for its launch.

The iPhone maker is not alone in targeting the car as a product needing disruption -- Google has been very public with its driverless car efforts -- but it may be the best-suited to bring something truly radical to market. Apple has shown a unique ability to make high-end technology palatable to consumers. It also has incredible brand loyalty, with millions of customers who follow its every move.

In launching a car, Apple would be taking on an industry with a very established way of doing business. The company has a high level of trust with consumers. It's that trust that might be the most important when it comes to getting people to embrace what may be a radically different vehicle.

If Apple, as expected, delivers an electric car it would be well-poised to move these vehicles beyond their current niche market. If the company can accomplish that, it could ultimately end the world's reliance on fossil fuels on a much faster timetable than the current auto industry appears set to do.

Environmentalism is a core principle at Apple, so it makes sense that the company would want to contribute to improving the air that we breathe and improving the sustainability of transportation.

Tim Brugger (Alphabet's smart homes): Alphabet's Q2 was solid, to say the least. Perhaps most intriguing -- even more so than its 11% jump in total sales -- was its "other revenues" climbing 17%, to $1.7 billion. Other revenue is where Alphabet's smart home sales reside, along with app revenue and the like. And based on new data, it appears Alphabet's Nest smart hub and assorted smart home solutions are poised to skyrocket, so keep an eye on other revenue.

It wasn't long ago that industry pundits were predicting smart homes were on the verge of exploding, and it appeared they were right -- at first. But in the U.S., adoption of smart home "things" has stalled at its current 10% market share. The problem has been that, as with most new technologies, early adopters are instantly hooked, but the technology won't change the world until it goes mainstream. Cost and a lack of awareness have also slowed smart home growth.

However, recent estimates suggest Alphabet and others are close to breaking down the barriers to smart home entry, and its Nest hub and existing partnerships with leading home gadget makers, like light bulbs , locks, and even baby monitors, give it a significant jump-start. According to Alphabet, its Nest Weave technology will also help bring smart homes to the masses, in that it now solves one of its biggest hurdles: allowing disparate systems to "talk" to each other. When Alphabet introduces Weave to developers next year, its Nest hub will become even more dynamic.

There's certainly a lot of revenue at stake. In five years, smart homes are expected to generate nearly $60 billion in sales. When smart home market estimates come to fruition, Alphabet will lead the charge, and the world will never be the same.

Daniel Kline owns shares of Apple and Facebook. Jamal Carnette owns shares of Apple. Tim Brugger has no position in any stocks mentioned. The Motley Fool owns shares of and recommends Alphabet (A shares), Alphabet (C shares), Apple, Facebook, Lions Gate Entertainment, and Netflix. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.