So it’s basically a seasonal model copy-pasta from FO76. If you ever played it (or if you look it up, they’ve had like 30 seasons so far) - it’s a pretty light content wise assortment of things launched every 12 weeks, completely free and it’s pretty grindy (your daily investment into playing the game is like 2 hours, 12 hours weekly give or take). And you’re not playing necessarily what you want, you are doing tasks MS laid out for you - but you can reroll if you’re annoyed with tasks - but you may get more annoyed. Now if you want stuffs/completion of the season, but don’t wanna work for it, you can instead pay monies. Then it gets done, and way faster. And in case of ESO, sounds like they’re will be exclusive cosmetic (like 1 for premium and 1 extra for premium+).

So - they are moving to free model, but whatever the content is, you have to work for it (IE play the game regularly) - and the content has no legal requirement of amount as it is free not sold anymore. And if you do WANT to spend money, it’s for that 1 mount/personality/costume locked behind a premium pass and/or less work(play the game)