Ok, first thing about VST vs. analog is that the analog we think of, the analog sound we think of is the sound of those old synths from the 70s. They were all wonky, hard to tune and units of the same synth sounded quite different from each other. That sort of randomness is quite hard to emulate, and thus VST’s can’t quite get there. They just sound too clean, too good. I bet there’s VST’s now that can come REALLY close, but when played next to a beat up old MS-20, the VST will not sound the same.
That said, as we get closer to modern times and analog synths became more realiable and clean, a VST can emulate them really well and honestly be indistinguishable, especially in a mix. Modern analog oscillators can sound extremely clean and steady (see: A4) and honestly kind of sound like a VST, hah. So, the question isn’t really whether VST’s sound like analog, they do, but what kind of instrument can you emulate digitally. You can’t emulate a guitar, still. Too much small variation that cannot feasibly be programmed into the VST. Same with old, technologically primitive synths. Too much variation within the circuitry, the small defects in the sound are what makes them sound huge and warm. Hard to program those in.
You can’t really emulate feedback digitally, either.