LastPass was founded in 2008, and an 8 character master password was clearly inadvisable back then, as it was already in the nation-state-can-crack-it territory, and computing power was rising rapidly.

I started using 1Password in ~2010, not long after the founding of LassPass, and my first master password was 30+ characters, 90+ bits of entropy. After a few years I upgraded to 50+ characters, 140+ bits of entropy. Good luck cracking that even if only one round of PBKDF2 is used.

But I suppose you have a fairly loose definition of "security-minded".