The part you're probably thinking of is GSync vs Freesync which is a feature for making a tear-free dynamic refresh rate, something that was simply impossible in the CRT days but does add some perceptual smoothness and responsiveness in games. Not using a compatible monitor just means you're doing sync with the traditional fixed rate system.
What has gotten way more complex is the software side of things because we're in a many-core, many-thread world and a game can't expect to achieve exact timing of their updates to hit a target refresh, so things are getting buffers on top of buffers and in-game configuration reflects that with various internal refresh rate settings.
We could write to buffers at 60 Hz effortlessly with computers from 1999, speeds have increased more than enough to write to buffers at 120 Hz and more, even with 16x more pixels.
1/120th of a second is a huge amount of time in CPU/GPU clock ticks, more than enough to compute a frame and write it to a double buffer to swap, and more threads should make that easier to do, not harder: more threads can compute pixels so pixels can be put in the buffer faster.
If there's problems with connector standards, software side of things, multithreading making it require third-party complexity, then that's a problem of those connector standards, the software, things like the LCD monitors themselves trying to be too smart and add delay, etc... Take also for example the AI upscaling done in NVidia cards now: adding yet more latency (since it needs multiple frames to compute this) and complexity (and I've seen it create artefacts too, then I'd rather just have a predictable bicubic or lanczos upscaling).
Same with audio: why do people tolerate such latency with bluetooth audio? Aptx had much less latency but the latest headphones don't support it anymore, only huge delay.
fun fact: the very same technique used by Freesync, delaying the vsync, works with CRTs
Genericness of Variable Refresh Rate (VRR works on any video source including DVI and VGA, even on MultiSync CRT tubes) https://forums.blurbusters.com/viewtopic.php?f=7&t=8889