VNC is so bad, it's god's joke against computer users. Apple's implementation of the VNC server is a joke upon a joke. Every MacOS release rounds the same circle of bugs, 1 release having broken security, the next release locking up during fullscreen blits, the next release having broken security again, none of them trapping all of the frame buffer changes. The mane problem with VNC, besides Apple's incompetent hiring practices, is it tries to passively detect frame buffer changes rather than being in the drawing pipeline.
It can compare every pixel of the frame buffer in certain time intervals or try to sniff drawing commands by checking CPU usage. It seems to rely on sniffing drawing commands, most of the time. Lions don't know because MacOS is closed source. It never works, no matter how fast the network is. It misses most frame buffer changes, severely delays the ones it catches, or just crashes.
Little of the internet knows before VNC, there was already a fully functional, superb protocol known as X11. That forced every drawing command through a single network socket. Running programs over a high speed network was like running them locally. It never missed a drawing command & responded instantly. By 2001, X11 had been extended so the same programs without any changes could run on a local display, without the network layer.
The world picked VNC because of its extremely short memory & the desire to reinvent the wheel to make money. VNC is the corporate desire to replace i = 0; i < 5; i++ on Monday with i in 0 ..< 5 on Tuesday, then i in range(0, 5, 1) on Wednesday & use each one as an excuse to split your stock.
It's a real problem of human nature. Humans exist because of luck more than intelligence.