While I get the issue with BGW not opening Pantheon....for people that have kept passes for years and years without Pantheon and in years that they haven't opened anything new to say you won't renew because of this is sorta hyperbole to me.
Anyways, some of those other parks named (KD, SFGrtAd) that have opened things have something different than BGW: Those parks/chains saw losses of passes and/or were actually sued for "breach of contract" over taking payment and not being opened. They had their reputation dinged during the pandemic, were closed much longer so they needed to boost attendance, they didn't have events going on. So from their standpoints, opening up new rides was a way to get people reinvigorated in their brand/park.
Over on BGW/SEAS side, they were one of the first to open back up. They have had different events going on. They gave a break in payments for some time. They have been rewarded for this by having a full park all day long and not needing a new attraction to draw people in the door. Yea it sucks for the (guessing) small percent of overall membership purchasers that bought just because of the Pantheon benefits to not get it in the year the bought it, but I'd be willing to bet they still give the benefits.
EDIT: Forgot to add that someone is bound to say "But Candymonium..." Well Hershey was supposed to host CoasterCon 2020, so they definitely needed to have it open and have the kinks ironed out. Due to, well we know, CoasterCon was pushed into 2021. I'd be willing to bet that if BGW hosted CoasterCon this weekend and had it pushed backBGW would have made sure that Pantheon was open.