I agree with your extremes that D3s shouldn't be able to scout half the country and that D2s shouldn't be able to scout the entire country, *AND* I think there's a ton of ground between that extreme and where we are currently.
I'm planning to bail on my D2 in Iba after this season & take a D1 job, so I decided I want to sign the best projected-D2 guys I can get in RS1 rather than depend on simmy (or possibly a human) to close the deal in RS2. I have 6 openings. I obviously should've done the math first, but...
Thought I could scout every projected-D2 recruit within 500 miles to at least level 3, but didn't even get close. I did a 200-player camp for only D2 players. Did FSS for D2 in my surrounding area. Then started doing D2 assistant searches thinking I'd run out of players before I ran out of money. (I was wrong... oof!)
That 500-mile radius is maybe 1/4ish of the country, but I was only scouting D2 guys. My recent scouting in FL messed me up on using the radius. I realized that a lot of the 500-mile radius from S. Florida (Barry in Tark) is the Gulf of Mexico & the Atlantic Ocean... but clearly I underappreciated how many more players are within 500 miles of Tigerville, SC vs Miami Shores, FL.
All that to say...
By limiting my scope to only D2 players I eliminated the problem of wasting scouting $ on top-100 players while also eliminating a lot of D1 players I'd likely be going after if I planned to stick around at this school beyond this season - and I still didn't effectively scout 1/4ish of the country, much less half or all of it. And this is with 6 openings. The D3 I "paid my (one season) dues" at only had 2 openings, and that scouting budget was part of why I posted these thoughts. D3 coaches want to find D1 guys who might drop down, and it sucks for very limited D3 scouting dollars to be wasted on top-100 guys and on guys you don't want to scout past level 2 or 3 - but there's currently no way to take advantage of the efficiency of bulk scouting *and* avoid wasting money on those players.
I also think this would add a "real life factor" (while enhancing the game) with the obvious fact that top-100 players aren't going to camps at D2 or D3 schools in real life, and D2 & D3 scouts aren't wasting their time either on top-100 players who will never go D2 much less D3 or on players who aren't worth scouting further.