I'm bored and desperate for attention, so I'm going to write the following sh!tshow of a response.
I'm uniquely qualified to address this issue, as I ran DI on a very MINOR athletic scholarship (I think it was like 1k at most...so, like, books) as a freshman at a not-prestigious school. I transferred after that first year to a DIII school and ran the rest of my "career" there. The caveat is that I was a sprinter, not a distance guy.
As a freshman, I was likely an above average-to-above-average DI sprinter. I took 5th as a true fresh in the 100; but our conference was not prestigious. I ran before the regionals system started but I might have made qualified to a theoretical regional that year by the skin of my teeth. I would not had any chance to go beyond that, obviously.
When I transferred to the DIII school, my performance suffered immensely due to the combination of me being a head case, injury prone, and the coaching was an absolute JOKE at the DIII school. Typically I focus on the coaching part but, eventually my "talent" won out and during my last year and a half I broke out again and started running well above average for any division. I ended up anchoring a national championship winning relay. Full disclosure; I never won an individual title despite running top 5 (at the time, anyway) all-time DIII times in the 100 and 200. The coaching never improved at the school, but I was a head case enough that my delusional belief that I was underperforming finally resulted in whatever I was throwing at the wall for training finally sticking.
I REGRET transferring. But it's complicated; I regret it laregly because of the downgrade in coaching I recieved. It also cost more at the DIII school and some of the reasons for my transfer became moot (I washed out if the DIII soccer team), but mostly the regret is the coaching sitch I ended up in. I transferred to the DIII school with the my eyes fairly open: I knew the coaching might not be quite as good but thought that wouldn't bother me that much after my "success" my freshman year. But the coaching was laughable enough that it became clear it was individual to THAT school; other DIII schools could have provided better sprint specific coaching than where I ended up at.
I ran fast enough at the end of my career that I would have been pretty good even in DI. I never won my individual DIII title mostly due to injury, but I was the fastest DIII for probably two years, and probably by quite a bit my last year. That last year I would have had a small shot at being an All-American as a DI athlete even with the lack of coaching I had recieved. Honestly, being a sprint nerd, I would have actually preferred to have gotten the DI All-American cert., even if it was just 8th place, than if I had ended up with the actual DIII individual title. But I also wanted to keep running after college; I cared a TON about reaching my maximum potential, even if it only mattered to ME what I did. Hence all my transfer regret with the coaching.
But if I could have had some semblance of the coaching I got my freshman year of college at the DIII school, then I could have been appeased with that. I think a 100m All American cert. is probably a bit more impressive than a DIII 100m title, but it's subjective. And if I had maxed out my potentially more appropriately as a DIII guy then I could live with the title and look at my PR and know my abilities. Hell, if you're good enough, you can just go to USAs a beat the DI guys there if you're legit enough (like a Symmonds-I vaguely hoped for some version of that experience but injury completely blew out that chance for me).
The problem is that there's an argument that if you go DIII, the coaching you'll get is worse. My experience would validate that. But, it doesn't HAVE to be that way. Find a legit coaching staff at a DIII school, and it's worth going there as much as anywhere. But maybe that's a diamond in the rough scenario.