All it really means is that they're the most effective skinner boxes yet devised as a way to keep people paying.

You argue that old-school MMOs were just grindfests that were designed to maximize subscription time. Minimal content that just takes months to grind out, so it feels worthwhile.

BTW this isn't to say that the old ones were 'good' or 'bad', just the opposite. Plenty of people like grindy MMOs like FFXI or OSRS, but plenty also like casual story-focused games like SWTOR or FFXIV or competitive stuff like WoW (at endgame).

Personally I would prefer something actually punishing instead of just tedious, something like a Dark Souls MMO or MMO-lite.