To answer the question posed in the title: because it's hard and the people with those skills are already getting paid to do it. It's also the answer to why the

To answer the question posed in the title: because it's hard and the people with those skills are already getting paid to do it. It's also the answer to why there's no free software that's as good as Photoshop. As others have said, the JVM has been a popular runtime target for the last few years. But it's been in constant development for a quarter century, and it powers countless enterprise systems, so the amount of time and resources that have gone into it are enormous. It's hard to get that level of investment in any software, period.