Reminds me of the phrase,

"When your barber starts giving you stock tips, it's time to sell"

What if the barber is the one who said this?

Russell's lesser-known paradox.

Does the barber shave himself or not?

Sell the barber.

I like that this phrase can be used to condescendingly dismiss two opposite viewpoints.

"Automation and globalization are going to destroy the world." -> "We've been saying that for a hundred years." rolls eyes "This time, it's different."

"Current tech companies might actually have a legitimate sustainable business that won't be totally obliterated in an imminent market crash" -> "Remember 1999?" rolls eyes "This time, it's different."

In all seriousness, though, we had one dot-com bubble; I am not sure it's wise to extrapolate that all tech companies now and for all time are doomed to fail after a few years. Particularly since the companies listed are actually profitable.

Huh? The companies mentioned were Microsoft and Cisco, two companies that were and are profitable. The "this time is different" was dismissing the idea that somehow growth is unbounded for this new crop of companies. No one mentioned the tech bubble of 2000ish or claimed that no one could build a sustainable tech company.

"This time, the stocks are generating cash profits"

Reminds me of the Nifty Fifty https://en.wikipedia.org/wiki/Nifty_Fifty

They were supposed to be big buy and hold forever stocks. Interestingly looking back if you had bought and held for decades you would have done ok with the food type ones - McD and Coke and poorly with tech like DEC and Kodak. It's hard to build a tech company that will still be good 30 years later.