Other than the fact that the ways around this are more complex, one or two monitors with the “fadtes/best” resolution doesn’t seem that different. Back when you needed a separate graphics card, the cards only supported one or two monitors, and there was only one “super fast” slit to put it in (e.g. only one 16x PCIe slot on quad G5; only one AGP slot for other configuration. True, you could add more PCI(e) cards, but they still didn’t match (at least in theory)mother ‘native’ card.
I don’t know enough yet about DisplayLink to comment on how much of a performance hit it is, relative to the above old days.
Curious if a thunderbolt-PCIe chassis with an old-style PCIe card would work, and if do, if it would be better.