I wonder how a convincing argument convinced you that the block can't be increased?
You're moving the goalposts a bit there. I didn't say I was convinced it can't be increased. Just that increases should be moderate.
If the arguments against increasing the block were convincing, then they should remain the same now. All you have to do is get them out, dust them off, and give them to the public.
In the end, I think it was ultimately more of an economic question than it was a technical one. Whether or not the Bitcoin network
could theoretically cope with larger blocks without sacrificing nodecount is completely immaterial if the nodes in question have no interest in allowing you to get past the first hurdle. It pretty much boils down to
this. We can argue over technical details for the rest of time, but the fact is, the arguments mean nothing if the people who secure the chain simply don't want to offer more of their own resources in order to permit a further increase beyond what SegWit is already achieving.