I'm not assuming they capitulate under just pressure. Rather I'm assuming they'll capitulate if a majority of or even all of the big third party chromium browse

I'm not assuming they capitulate under just pressure. Rather I'm assuming they'll capitulate if a majority of or even all of the big third party chromium browsers push for adding it to mainline chromium. This is less just blind pressure but rather the risk that google becomes seen as an untrustworthy custodian of chromium and that downstreams start supporting an alternate upstream outside of google's control. Jxl is certainly a hill that google seems intent to stand on but I doubt it's one they'd choose to die on. Doubly so given the ammo it'd give in the ongoing chrome anti-trust lawsuits.