This is the biggest problem right now, at least for people like me.
I know what was part of their past continuity, and I know what DC seems to have set up so far: that the members of the JSA disappeared from their HUAC-type of hearings in the early 1950s and haven't been seen nor heard from since, at least as far as Johnny Thunder is aware; and that almost nobody else seems to remember or have heard of them at all.
Until DC can explain what exactly happened; which members went missing (was it all the costumed members with secret identities who had been a part of the JSA, or just ones still active at that time); where/when the missing members have been gone to; or even if it's just Johnny Thunder who was removed from the Earth the JSA had been active on and finds himself trapped in a world he hadn't previously been living on, it's hard to say what DC may do about all this.
But if they, once again, try to pretend they're "bringing back" the JSA only to foist upon us a pseudo-JSA that only partially resembles the group many of want back, it unfortunately wouldn't be surprising. Just look at what Geoff Johns did with Barry Allen.