Would a technical solution (web decentralization) really be necessary if a political solution (adequate regulations) was available for these issues?

I am very dubious that could happen, for two reasons.

One that the big centalizers have too much political influence, at least in the US, and let's not forget places like China and Russia where the governments to control the web.

But even if you passed some strong regulations, the centralizers would likely keep coming up with new innovations that would break the spirit of the laws.