Attorney here. It’s very possible that lawyers won’t be working on this for “years to come.” They need plaintiffs, after all, and many real or potential cases may already have settled out. And other passengers may just wish to put the Sky debacle behind them, five years after it occurred. (There’s also the issue of potential statutes of limitation, but that’s beyond the scope of this comment.)
As to the ascertainment of legal responsibility, courts do this all the time in multi-party litigation. It’s not a problem.