SOs have the good fortune to get fired if they do not make it on to the FO pay scale.
When they eventually get an upgrade, yes.
But the SO scale only goes to 4, and quite a few of them are about to max it out, or have already.
As you said, every new year, the payscale looses a few percent on account of inflation. Every new joiner is faring a bit worse than the guy who joined just before, and any though of an adjustement to the payscale is but a distant dream to the most optimistic of us.
All we get is a percent or two every year + the increment for those who haven't maxed the scale yet, which doesn't even compensate for the increasing cost of living. (Let's no even talk about the all but forgotten 13th month).
Incremental payscale should be kept as it is a reward for your years of commitments to the airline, but there should be more awareness of the fact that increments aren't there to compensate for inflation and aren't generous 'salary increases', as management would have us believe.