They need to do something quick. I will never purchase another Samsung phone (non-nexus) again for this purpose. I only bought the infuse for my wife last August when they incorrectly announced that GB would be coming soon.
I'm pretty sure it's more of an AT&T issue than Samsung's. The Droid Charge which is also by Samsung, which came out at the same time as the Infuse, was on Verizon and it also shipped with Froyo.
They got their Gingerbread update via OTA in November.
I'd say rather than avoiding Samsung devices (since they undeniably are producing top of the line ones), if you are concerned about updates, stick to a flagship phone. The Galaxy SII will get Samsung's #1 priority as far as receiving developer attention/updates/bug-fixes.
The Infuse was released as a niche phone and its owner base is far smaller than the number of people who own Galaxy SII, so it's unavoidable that it's going to get pushed down on the priority list at Samsung/AT&T.
I just hope the Gingerbread update comes soon within a week or so!