Nah. Declining industries take plenty of time to decline, more than enough for those there to finish out their careers in comfort. Just look at west coast shipping and the rise of containerisation. Labour solidarity absolutely works, not for saving industries but for saving humans.
In my personal experience, unions will prioritise the interests of senior members approaching retirement over fresh graduates coming into an industry. If you are in the latter group, breaking with “solidarity” may be more in your personal best interests than going along with it
Thats depends on the specific disruption that is happening to the market.
As stated, you can push at the edges. But no amount of incremental pushing stops 100X cost reducing disruptive technologies that are widely available to the public and that can't be banned unless all personal PCs are confiscated.
Inertia really does seem to keep dying industries around for longer than seems reasonable because humans aren’t completely rational actors.