On many bikes I have the same width and bend of handlebar, a model I first fitted over 40 years ago.
Stem length varies by top tube length, (as measured forward of a vertical line through the BB center)
Some bikes have a short front center and top tube, they get a longer stem to get the key dimensions the same.
Handling is effected of course, so you select the bike for the ride planned.

I bought a French bike a few years ago with of course French parts and sizing, so more effort to change and a top tube at the shorter end of my typical size range. After setting the saddle position, I found the existing "cockpit" (not totally friendly with that term) was spot on in the hooks and on the hoods, but as the forward throw of the bar is much longer, the stem is short, by over 2 cm compared to what I would expect. The has become my go-to climbing bike, Andy Hampsten nailed it with a comment, paraphrasing, who do you see climbing in the drops for a sustained period? On his Giro winning steed, the stem is set much higher than when racing elsewhere. More Upright is the way to go for climbing.