Them being let go "because they didn't meet 5x" is hearsay. The only source for that is in social-media commentary and opinion pieces. Microsoft described the layoffs as "organizational adjustments".
Wow, know you make me curious about the business processes at Microsoft. Did they see that they would earn more money if the interpreter had a 5x speedup, that they wouldn’t see with 1.5x?
Or was it trust broken?
Instead of generating more revenue, it would drive down costs. You will need less computers to do the same amount of work if the work can be done faster.
Python is slow due to design decisions in the language. For example operator dispatch is slow without some kind of static analysis. But this is hindered by how dynamic the language is.
It's hard to make Python run fast when it pervasively uses duck typing. It makes types only resolvable at runtime. JIT is the only thing that can work here at the moment, but I think that needs to make very similar assumptions to a branch predictor, plus it needs to identify lexical regions (is that what they're called?). People here have criticised PyPy, but I've forgotten why.
It’s wildly optimistic to now expect a 10x speedup in two years, with fewer resources.