Another quarter is in the books for media and entertainment outfit Comcast (CMCSA -1.10%). As one might have expected, its movie and theme park businesses continue to heal from the impact of the pandemic. But its cable television business continues to implode.

All told, Comcast's cable service -- you know it as Xfinity -- shed another 408,000 customers last quarter, bringing the attrition figure up to nearly 1.3 million through the first three quarters of the current fiscal year. That's more cable subscribers than it had lost through the first three quarters of last year when COVID-19 lockdowns gave consumers plenty of time and reason to cancel their cable service and look for cheaper alternatives.

That's a problem for an organization predominantly considered a "cable company."

A crowd of people merging into a rising arrow.

Image source: Getty Images.

The thing is, as time marches on, the slow implosion of the cable television business (and Xfinity's piece of it) matters less and less. That's because Comcast is more than offsetting those customer losses on two other fronts just within its cable communications unit. One of them is a bit of a shocker.

Growing where it can (and should)

Don't misread the message. Given the choice, Comcast would rather keep its existing cable subscribers and add new ones through its other offerings than lose any paying customers. But that's not a choice the company faces, a reality CFO Mike Cavanagh conceded back in 2019 by commenting that Comcast is "not chasing unprofitable [video] subs." True to his word, Comcast hasn't, hence its cable TV arm's continued contraction.

The company has, however, taken the next-best possible course of action: ensuring it makes forward progress in the one market that's helping to upend the cable television business it's also in. That's broadband. It picked up another 300,000 high-speed internet customers during the third quarter ending in September to bring the year-to-date total up to a little more than 1.1 million. That's not as many as it added last year, for the quarter or through the first nine months of the year. But it's solid follow-through given the surge of demand seen last year when millions of people were suddenly forced to stay at home yet find a way to remain connected with the outside world.

Take a look at the bigger trend in the chart below. (Also bear in mind that although this is not seen in the chart, the high-speed internet business is more profitable than the cable television business, as providers aren't beholden to the often-costly demands of programming suppliers like TV networks or cable channels.)

Comcast's cable communication overall customer count continues to grow even if its cable business is shrinking.

Data source: Comcast.

As the chart also illustrates, Comcast is getting serious traction with its young wireless business, picking up another 285,000 wireless subscribers during the third quarter alone. This unit's growth is accelerating, in fact, which is an impressive feat considering the mobile service is only offered to Xfinity internet customers. Between last quarter's addition of wireless and broadband subscribers, Comcast more than offset its cable TV customer losses.

It's not much of a cable company, even if it's in the business

Again, the company would obviously prefer to keep its cable customers while also adding high-speed internet and wireless customers, making the very most of an infrastructure that can handle all three services. That's not a plausible option, though. Investors can take solace knowing that despite dire headlines about the cable business, Comcast is better defended than it may seem on the surface. It's even participating in its own cable demise with its streaming service, Peacock; such alternatives have made it incredibly easy for millions of people to cut the cord.

Here's another detail that current and prospective Comcast shareholders can take comfort in: Cable television isn't the bulk of this "cable company's" business. It's not even the company's single-biggest unit. That size honor is actually fairly evenly split between broadband and the NBCUniversal media arm. Year to date, cable TV revenue only accounts for about 20% of Comcast's top line.

The point is, don't jump to the wrong conclusions about Comcast that are all-too-easy to jump to. This company isn't what many people think it is.