"why hasn't someone come out with a solid replacement?"
There are some companies/people keeping the torch burning but they're not as widely known, one such is Mercury which targets a whole host of platforms and is actually quite good - https://www.remobjects.com/elements/mercury/
The problem is it feels a bit of a niche language now because MS basically forced people on to C# by not actively maintaining VB.NET which was the first hop for people coming from VB. Early in my career I did various conversion projects for corps from VB to VB.NET then eventually as that atrophied to C#.