Over the past 5 years, COST has traded at an average PE of about 39. Over the past 10 years, average PE is about 34. Current PE is 46. Not in bargain territory even by its own current standards, which are lofty.

True enough.
It also seems that their normal lofty level has itself been rising for quite a while now.

Conveniently their EPS rise so smoothly that old fashioned P/E makes a reasonable yardstick.

Average trailing earnings year 20 years ago through 10 years ago equated to a P/E of 23.2
From 10 to 5 years ago that average was 28.9
In the last 5 years, 38.1.

So, if the last 5 years are the new (and presumed future) normal, then the current figure is only 21% more expensive than usual.
But if the old normal 10-20 years ago is the presumed future normal, then the current figure is 97% above expected.

I guess the only thing that pulls it down is a widespread bear. It traded down to a "mere" 21 for a while in 2009.
And when those disruptions happen, there are so many tempting targets that it still never seems like the best choice...so I never buy it.

Meanwhile, of course, they just make more and more money. The trend line of real EPS is a juggernaut, rising inflation + 8.78%/year in the last 20 years. Perhaps even a titch faster lately. Plus about another 0.6% in dividends.

Like so many people, I'd buy it if it got cheap. But since there are so many people like me ready to buy on dips, I have a hunch the stock price will generally stay well supported.

Jim