The point is that we can improve latency of even old machines by simply attaching a display output that supports a higher refresh rate, or perhaps even variable refresh rate. This can negate most of the unavoidable latency of a compositor, while other techniques can be used to avoid compositor latency in more specific scenarios and try to improve performance and frame pacing.
A new display is usually going to be cheaper than a new computer. Displays which can actually deliver 240 Hz refresh rates can be had for under $200 on the lower end, whereas you can find 180 Hz displays for under $100, brand new. It's cheap enough that I don't think it's even terribly common to buy/sell the lower end ones second-hand.
For laptops, well, there is no great solution there; older laptops with 60 Hz panels are stuck with worse latency when using a compositor.
Plenty of brand new displays are still sold that only go up to 60hz, especially if you want high quality IPS panels.
They aren't as common now, but when making a list of screens to replace my current one, I am limiting myself to IPS panels and quite a few of the modern options are still 60hz.
Yeah, I personally still have a lot of 60 Hz panels. One of my favorites is a 43" 4K IPS. I don't think I will be able to get that at 120+ Hz any time soon.
Of course, this isn't a huge deal to me. The additional latency is not an unusable nightmare. I'm just saying that if you are particularly latency sensitive, it's something that you can affordably mitigate even when using a compositor. I think most people have been totally fine eating the compositor latency at 60 Hz.
A new display is usually going to be cheaper than a new computer. Displays which can actually deliver 240 Hz refresh rates can be had for under $200 on the lower end, whereas you can find 180 Hz displays for under $100, brand new. It's cheap enough that I don't think it's even terribly common to buy/sell the lower end ones second-hand.
For laptops, well, there is no great solution there; older laptops with 60 Hz panels are stuck with worse latency when using a compositor.