The model hasn’t changed, but as development of new content has continued, 95% of new content is subscription only.
That said, I can’t speak for Runescape “proper” aka Runescape 3, the current “main” version. I’ve heard a lot of concerning things about all sorts of mobile game style predatory shit going on there.
I’ve only played Runescape 2, now called “Old School Runescape”, which is a fork of the game from (I think) 2006.
Essentially, right around that time they completely overhauled combat, stat progression, and a bunch of other stuff, and called it Runescape 3. A lot of people didn’t like the changes and started hosting custom servers from before the changes.
Eventually they made an official version, called it Old School Runescape, and have been developing it side by side with “normal” Runescape since.
Old School isn’t predatory in my opinion. Outside of occasional “leagues” on special servers with specific challenges applied, there’s no FOMO. The f2p game has plenty of content enjoyable on its own. The subscription just unlocks a mountain of more content, including alternative ways to level up through early game. Technically you can advance faster with a subscription, but that’s due to having more options to turn into an over optimized plan, not some shit exp multiplier or something.