It's easy to imagine they wouldn't have just countered anything. It's as easy as it is to imagine the other because imagination is just what it is; not reality. We realistically have no idea what the Dodgers were going to do, it's best not to assume otherwise. Instead what we know right now:
1. The Dodgers offered prospects, based on how the industry views them, as "surplus to needs". Hope is routinely the third ranked OF'er in their system
2. The Brewers and Rays did not offer a package that was deemed more than the Dodgers to Scott Harris and the Tigers.
3. What the Dodgers offered seems to line up with historic trends for this type of a move.
This could have been because of lots of reasons. Maybe Harris loves River Ryan; certainly plausible he has some of the best Stuff+ in all of the MiLB and it's easy to dream on. Maybe the Brewers and the Rays didn't offer more or wouldn't budge; certainly plausible with how the two handle prospects and may need them. There are far more.
I think had the Brewers and the Rays been as convinced as you are here that they would have just kept beating their offers, that they probably would have forced that hand. Why wouldn't you force the Dodgers to trade more if it's as simple as "everyone knows they were just going to keep going"? Make 'em do it. So I'm not sure it's as cut and dry.
My entirely uninformed opinion is that the Tigers like the Dodgers' package more than some do. If you see River Ryan as a front line SP who's ready to jump into a rotation right now, I think it's hard to beat the Dodgers' offer of a COF bat and that. If you're skeptical about the health and the age on River Ryan, than you got a non-premium position prospect and a 28 year old with a lot of reliever risk. I'm more in the second camp. My uninformed opinion is that Harris is in the former more than the latter.