Not true - you can partake in it and complete the 4 star tier as FTP.
They just gated 7 star unlocks behind a paywall, and for me (and probably others) that's actually a pretty good thing in the long run as it makes ressource management way easier.
I consider myself a "dolphin". I spent a decent amount over the years, but the times I went full whale on stuff is rather limited. Up until the "Era"-era, I would spend crystals and cash to get the 7 star toon at once, which would give me the opportunity to unlock new legendaries in the first event run or get GLs relatively early on. That was my only motivation: Getting the new legendaries on the first instance of the event.
With the Era-system the amount I have to spent is just jacked up so incredibly high, that I won't even consider it.
This leaves me with no other choice than to stop spending crystals and money on unlocking 7 star marquee toons. Because why would I bother? They are locked away in the brain dead era-system for months and I can't use them for anything other that losing brain cells in colosseum. Furthermore I have NO chance at getting new legendaries unless I spend a lot extra on era-levels on top of the 7-star unlock.
"bUt WhAt AbOuT rELiC 10?!" - well, I don't really care about the daily rewards, since I'll probably be able to stay in the 100 era currency bracket no matter what. And the top two reward levels are reserved for spenders anyway, so those are not accessible anyway. And so far I don't really feel that relic delta is too much of an issue. Even though I'm in a 600M guild, the amount of R10s are neglegible. The materials are so hard to come by, that nobody wants to apply R10 to anything on the fear of having to wrestle R10-requirements soon. Therefore I don't really care about R10 right now. It's a novelty at best.
All in all I'm way better off just hoarding crystals, gear and relic materials and wait until the toons are released from Era Prison. Then I can spend my crystals on shards from shipments, which will actually give me around twice as many shards that the crystal shard packs do now, and I will have no issue farming gear an relic materials to take the new toons all the way to at least R7 when I finally get them to 7 stars.
So, yeah, it sucks that Eras is the end of me unlocking new legendaries day 1, but at least the decision is pretty easy. I would have been a way more difficult choice if they had just increased the over all price slightly. But thankfully CG chose to go full re-tard ...