PA Semi was 2008 or so, and Intrinsity in 2009-10. In both cases they came with (more or less) working products, an existing relationship, and coherent engineering teams with an active development pipeline. Its fair to say the intel modem folks have a lot of that individually, but Im not clear how much of the whole transferred over.

Edit: and the HwEng org already had established VLSI, SoC, and PCB groups shipping products before those acquisitions happened.