Huh, I've only ever heard of MST in the context of too-high-res displays o_0 Never heard of raw DP supporting daisy chaining, I thought only Thunderbolt does that.
Thunderbol/USB C use displayport signal to drive monitors. I have a apple "thunderbolt" display which happily runs from laptops that don't do thunderbolt.
Dell makes some Displayport monitors which support daisy chaining.
My favourite example is one that the OP mentioned - not supporting multiple stream transport on Displayport. For those who aren't familiar, Displayport MST is a feature that allows multiple streams over one Displayport cable. Some monitors support this directly, meaning you can have
rather than This is great, and it really helps clean up your desk in multi-monitor setups and maintain that "one cable" philosophy that I, personally, love. And macOS supports MST too, which is great.Except they don't support it for this.
What they support MST for is to allow vastly-higher-resolution displays on macOS, such as 5K displays, by splitting the display image over multiple stream transports to bypass the limit on resolutions and refresh rates that Displayport provides (or provided at the time).
For some reason, they just haven't bothered to implement MST to allow for multiple displays; it exists and is supported, but only for high-resolution displays. This is great if you're googling around and see that macOS supports MST, then you buy monitors which support MST and hey surprise it doesn't work and there's literally no indication why.