Ada has multiple implementations, is pretty safe, and produces fast code. Yet it isn't popular, so I guess there are other factors that are more important than number of compilers and speed.
languages suffer from the same network effect as social networks. You could argue that Ada is a better programming language or that Ithkuil is a better spoken language but unless other people are also using them, you'll struggle to get help or hire people (or get contributors).
Ada isn't my favourite language to code in. But if I was tasked to build something safety-critical, I would strongly consider Ada SPARK [1] among the possible tools to use.
