I inadvertently answered your question. I am not speaking for the current season only, or the coming 2-3 years, but long term. If 4.5 remains our ceiling for the next 10 years, we are going to have a hard time competing in Europe. Serie A is a mere shadow of what it used to be, so I don't use it as the real benchmark. How well we perform in Europe is a more representative and truthful assessment of our true abilities.
I would like to think that for all the "sacrifices" we are making now, we should be able to become more competitive in 3-5 years.
Regarding the wage cap, I don't know what it is, and doubt anyone else does

I am all in favor of introducing a salary cap for all teams, and a ceiling on transfer fees, but I highly doubt that is ever going to happen.