It's really not that complicated:
The very best D2 and D3 runners could all run for virtually any D1 team. Very, very few of them would qualify for D1 nationals.
That makes it extremely difficult for a D2 or D3 team to field a relay that could compete with D1 teams. There are plenty of small colleges with a guy who can run 4:10, or someone who can run 1:53, or someone who can run 3:05, or a 48-second guy. There are not many schools with all four.
Plus all the stuff about tactics at nationals, it is quite unreasonable to expect sub-9:50 DMRs there.
So if you're a D1 guy who can't stand a "national champion" team running 10 flat, then you should have found three friends to go D3.