Costco Wholesale (COST 0.17%) just reported healthy fiscal fourth-quarter results, topping most expectations for its top and bottom lines. But investors aren't thrilled. Shares dropped following the release of its quarterly numbers, weighed down by (legitimate) worries that inflation is even taking a toll on this perennial powerhouse.

This line of thinking, however, ignores three bullish takeaways from the company's quarterly numbers. Costco is still the solid buy it's been for the better part of its stock's history, and this year's sell-off, extended by last week's continued weakness, makes the ticker an even better bet now.

1. Its membership fees are sound -- despite what some say

At least part of the recent round of selling stems from Costco's decision regarding its annual membership fee. Some investors want the company to raise fees as a means of combating pressured profit margins, mirroring a recent fee increase imposed by rival club-based retailer Sam's Club, owned by Walmart. Costco, however, has no plans to do so at this point in time.

As the old adage goes, if it ain't broke, don't fix it. Last quarter's top line of $72.1 billion is 15.2% better than the year-earlier figure, while same-store sales grew 13.7%. Per-share earnings of $4.20 are only an 11.7% year-over-year improvement, thanks to relatively higher product costs. But all of these numbers outpaced the comparable results reported by chief rivals Walmart and Kroger last quarter, confirming that the company is winning more than its fair share of market growth.

2. Costco is the inflation solution

The end result of Costco's fee strategy and subsequently strong sales growth makes sense in light of another metric.

Most grocery and consumer goods retailers are reporting respectable sales growth this year. But with the annualized consumer inflation rate standing in excess of 8% -- and still higher than 6% when taking food and fuel out of the equation -- it's difficult to determine how much of this growth is simply attributable to the higher prices people are paying for basic goods.

Costco's continued double-digit sales growth leaves no doubt in this regard, as more and more consumers are flocking to its stores in an effort curb their net expenses. The company ended last quarter with 65.8 million household memberships and 118.9 million cardholders. Both are up 6.5% from this point in 2021. And both are up from the prior quarter's comparisons of 64.4 million and 116.6 million, respectively.

Worldwide membership renewal rates rolled in at 90.4% in the recently ended fiscal year as well, and were even better at 92.6% in the U.S. and Canada. Both are also slightly stronger than Costco's reported retention metrics from just three months earlier, re-topping the record rates reached in that quarter.

3. E-commerce isn't everything (and may be a distraction)

Finally, while most retailers have been chasing Amazon as well as each other for a share of the e-commerce market, Costco Wholesale hasn't.

It does offer online shopping and some delivery options to certain members, for the record. But the whole digital thing hasn't been a priority for the retailer. Notably, the company doesn't offer curbside pickup at most of its locales, and instead asks its store-pickup customers to come inside to retrieve their merchandise. This may at least partially explain Costco's subpar 8.4% uptick in e-commerce sales last quarter, cooling off from growth rates seen earlier in the fiscal year.

What's so noteworthy about this lackluster online shopping growth rate is that it doesn't crimp the company's total top-line improvements. In other words, Costco is one of the very few big box retailers reporting sales growth not being led by e-commerce. It's an indication that the in-store experience is the right place to focus, perhaps prompting impulse purchases that wouldn't have otherwise been made by an online-only shopper.

Think bigger picture

Don't misread the message. Costco isn't immune to the inflationary headwinds currently blowing. Last quarter's net margin rates were pressured, and while the retailer doesn't offer guidance, analysts' forecasts for the year now underway partially imply a continuation of this pressure. Sales growth is likely to cool as well.

But look at the bigger picture here. The economy is -- for lack of a better way of describing it -- in a weird place where inflation is sky-high yet employment is still strong. It may well be edging into a recession, or maybe not. Either way, consumers still have to eat. They'll just have to eat more cost-effectively. All of it plays into the hand Costco Wholesale is holding, more so than any of its rivals.

This dynamic hasn't helped stave off a sell-off for the stock this year. Given the backdrop, though, the sell-off that's still seemingly underway sets the stage for an even stronger recovery once the market realizes Costco's resiliency.