I'm nearly at 7 with my employer and I've found the situation to be quite good and I see no sign yet to jump ship. There's still good gigs out there.
I'm sure the person you are responding to had good reason to stick around 20 years. It's possible only recently did the math not work out for them.
Curious, why do you remember day 1 for you?
I don't know mine. I do remember sitting in my kitchen at the family computer listening to the modem connect via an AOL disc though. Sometime in the late 90s if I had to guess.
Apparently in 1998 half of all cds produced worldwide had an AOL logo on them. Wild.