I'm sorry, I thought I was replying to the most relevant part of your post. But to address the rest of it:

Smaller bikes aren't "screwed" if they are designed with care. Shorter top tubes are possible with small frames without massive toe overlap by making the head tube stack, but then correcting for that slack by increasing fork rake to bring trail back to a useful range closer to neutral. With the same trail, bikes tend to steer fairly similarly despite differences in HTA.

STAs are also sometimes steeper on smaller bikes, but this is mainly done (it appears) to make ETT appear shorter. But some bike companies have resisted this. Cervelo uses 73° STAs on all frame sizes, for instance. And back in the '80s Cannondale was doing the same, as well has using well raked forks to neutralize fairly slack head tubes.


But some companies are lazy, use fixed rake forks across size ranges, cheat with steep STAs and have even raised BB heights to make it easier to assemble small lugged frames (Trek). But that's a shame-on-them rather than a built in problem of smaller geometry road bikes. At my last job we supplied a custom Seven to a woman who is 5'2" by using Seven's variably rake carbon fork and something like a 70° heat tube. It rode very nicely.