The problem isn't that Japanese companies "missed" the opportunity to do software at X point in time--the problem is that they are culturally Japanese. Japan is about consensus-based design, there is a high penalty for making mistakes, and individuality/creativity is not valued. 出る杭は打たれる - "The nail that sticks up will be hammered down". Certainly you can develop software this way, but the Silicon Valley model of rapid iteration, "if it doesn't work rewrite it", "move fast and break things", etc. gets you there sooner.
But what about Matz and the Ruby core team, you say? Certainly they are a zany, free-thinking bunch. I attended Ruby Kaigi last year and noticed that most Ruby core team members are hired by domestic Japan-focused tech companies, think Cookpad, Tabelog, etc. They are kept for their HR value to attract tech recruits and allowed to spend all their time on whatever open source project they want. Meanwhile the peons work on the actual product.
Source: I've worked in software in Japan for 15 years; 5 at a Japanese bank and 10 as a CTO of my own company. We run circles around our Japanese competitors.