I haven't checked the firmware however it was working perfectly well for a couple of weeks and then just started redirecting me to the "renew your subscription" page this afternoon. Is this a usual thing with a PS4?
Do you mean is it normal for SIE to release firmware fixes for issues ahead of time before the old servers die.. yes..
Do you mean is it normal for firmware updates to be optional.. No not realy... but if issues are only going to effect small number of accounts then instead of forcing all 90 nillion consoles then giving out an optional firmware fix won't hinder the other users...
Do you mean is the Number 1 fix for console and PCs is to see if there is an OS update, yes that normal..
Yes if you have issues thats the first fix. to see if there is a firmware fix for issues or see if the license renew in system settings fixes it...
Many others may have zero issues because they allready have the new firmware and don't connect to the same account server farm as you...