It's not a new thing. The Vax 9000 had multichip modules with a very very special interposer for the same reasons. The transistor density they wanted combined with the yields they were getting meant that they couldn't fit the whole design on a single chip, so they broke up the chip and tried to heavily control the cross chip interconnects more than you could if you went out to a PCB and back to sort of 80/20 your way to what a single chip would get you.

The difference now though is that it's not certain that yields will get markedly better at these nodes and smaller, whereas yeah, we got a lot better yields on much smaller nodes than 1750nm ECL logic eventually.