Why are some people saying the Colts won't make the playoffs?

Ive been hearing a lot of ysts and some people on here saying that without dungy and harrison, the Colts are not going to make the playoffs. It seems like people are putting a little too much faith in the Texans (who have never had above an 8-8 record) to upseat the Colts. i just dont see this happening, and i cant imagine the playoffs without the colts... unless peyton gets injured. what do you guys think?