Green, Duckett, and Foster were all well regarded. Not Bush's level, but high. Bush was certainly higher rated than Portis coming out. But regardless how they were rated, Portis (sprinter speed, shifty and great balance, decent hands) is a good model for what Bush might be able to do in the pros, Curtis Martin and Terel Davis too--also later picks. These guys all played like top 10 draft picks in the pros, the fact they were drafted later doesn't take away that.
3100 in his 1st two seasons is a ton. About 6000 yards rushing and 7000 total yards in 4 season are a ton. Champ Bailey is also 3 years older. He probably is considered the best CB today, but wasn't then. Denver also got a future Skins #1 draft pick. Brilliant trade by Denver, but fleecing the Skins hasn't been too hard of late. Back on point, no question Denver felt having one of the best young RBs (23 years old off of 3000 yard 1st two years) was not worth the oppertunnity of having one of the best corners (even if 3 years older) plus another future 1st rounder. Portis accounted for 2/3rds of the Broncos rushing his last year, and was by far their best back when they traded him (Quentin Griffin with 345 yards on 3.7av was their next best--let's not even compare with with DD), but they still saw the oppertunnity cost of trading him too high. I am not saying it means the Texans definetively won't take Bush, but if Kubiak had something to do with the Porsis trade it certainly doesn't work for Bush.