This meme about Python being slow needs to end. While it's not as fast as some other interpreted languages it is not slow for any general use case unless you're doing number crunching (which is slow in any interpreted/bytecode language anyway).
python being slow is not a "meme," it's just reality. The performance issue for a text editor or other GUI is latency, which is a difficult problem even when you have more control from using a lower-level language. A dynamic scripting language with a garbage collector is just not going to cut it. not to mention python's demonstrated history of becoming unwieldy as project size increases.
pythonistas either say, "it's not slow!", or, "it doesn't matter if it's slow". In some cases, it truly doesn't matter that it is, in fact, slow as molasses. But a text editor is not one of those.
Vy will probably be just fine, but considering people think JS is slow, I doubt the idea that python is slow will die soon.
If your performance benchmark is, say, computational fluid dynamics, then then pure Python isn't going to fare well since languages with less overhead will be able to more efficiently leverage the available hardware.
However, a text editor / IDE has relatively fixed performance requirements based on users' perception, such that selective optimization is tractable. Once an application can satisfy human expectations without devouring system resources, additional gains are moot.