Based on the criteria you mention (infrastructure, capital markets, regulation and market size), there most certainly isn't one. The other large countries have more onerous regulations and worse infrastructure than the US does.
But it's clearly not enough to say "the US isn't as bad as everywhere else" if everywhere else is merely drifting toward consolidation more slowly.
Is there a country that has better infrastructure, capital markets, regulation and market size? I am genuinely curious.