Modern Intel chipsets don't even support PCI and haven't for a few years. If an OEM wants PCI slots on their motherboards they've got to use a bridge chip that presumably taps one PCIe lane.
Incorrect. The Q and C versions of the desktop PCH have continued to include native pci controllers for a long time, including the current socket 1150. (or a built in bridge chip if you like)
More importantly they also work with almost any card as they implement PCI 2.whatever to full spec unlike those half-arsed ASmedia or whatever cheap bridge chips that a lot of OEMs use.
Source: painful real world experience. Similar situations exist for most 3rd party NIC and SATA controllers that infect many boards, those chips are cheap for a reason...
Ironically, knowing how intel bins everything
down to the 9th circle of hell because their 1st and 2nd death stars have been operational for awhile now and they are building a third:
it is highly likely
your Z/H/etc versions you own today actually have the same circuitry, just disabled. The OEMs playing the bullet point/market segmentation game find it cheaper to throw 3rd party chips on a board, and intel also gets in the way by not allowing overclocking etc on Q/C among other things. (If you really want to push my rant button, it only takes three letters: ECC)
BTW, people that whine about PS/2 can get bent. Despite its age, it is still the superior keyboard
interface vs USB.