I don't see how you can say that.
I say it because I have some (admittedly minor, but more than most) personal experience with the atmosphere and practices at game development companies. No publisher is going to fund someone digging out, relearning, and rewriting the source code for games that haven't been touched in 3 years or more. Especially on games where no semblance of the original dev team is still working for the company. Plus it's entirely possible (and sometimes even likely depending on the company) that they don't even have the original source code for the games anymore.
All the "fixes" they've done for the Windows native games have been limited to doing common config file tweaks that were already possible with the original versions. Republic Commando included.
I can confim bump mapping is disabled in Republic Commando. It's actually disabled at the driver level in newer nVidia drivers, it has nothing to do with the Steam version of the game. You can select "High" in game and it doesn't crash anymore and it's not corrupted, but you don't actually get any bump mapping at tall - they just removed it.
---Update---
Just saw your post over on the Steam forum which includes a screenshot. And yup, hate to break it to you, but bumpmapping isn't actually enabled. I know it says it's enabled in the options, but it doesn't actually work. You're missing the bumping detail on the character's armor.
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Easiest way to tell if bumpmapping is actually working is by the "speaker" details inside the helmet. If it's working they should look raised like this:
If it's actually disabled you get a flat texture like this:
You can also see the difference's in the character armor if you look closely; the ridges aren't as pronouced. It's very subtle in a screenshot, but much more obvious in motion. I'll echo what some of the people on the Steam forums have said. If you played it years ago when the bumpmapping was actually working properly, the differences are fairly obvious when you compare to new cards running the game with bump mapping "enabled".