By that definition, Japan has its own software companies too. They are also big in the gaming world. I didn't check the numbers, but I'd bet it's bigger than France.
The US has won the Software (ie: not the games, but the core Software market) because it had pocket deep VCs that understood tech. Everything else is secondary. This is of course, my opinion.
Yes, even in games this is the case. Market leadership in gaming followed market investment. Japan had a large manufacturing presence in games from early on which propelled the corresponding software industry. And the US was pioneering in funding pure software businesses - gaming became part of Silicon Valley's VC pool in the 80's. In other countries, they faced difficulty raising the capital needed to grow as productions got bigger in the 1990's, and mostly got absorbed by US investment, either through acquisition or talent poaching. Ubi was a rare exception to this trend.
I'm pretty sure a story similar to this was playing out throughout the software world.
The US has won the Software (ie: not the games, but the core Software market) because it had pocket deep VCs that understood tech. Everything else is secondary. This is of course, my opinion.