In the interview he said hes more interested in doing portal 2.
Most CSS players just want the bugs to be fixed, we dont want a new engine or better graphics or anything like that, just for the documented bugs to be looked at, things like interpolate delay, the random nade throwing animation bug, the screwed up hitboxes on the 'crabbing' bomb planter, and there are many others.
If a new engine is required to fix these bugs then so be it, but if its not required, then they should just update the game, fix these bugs, and I think CSS would last another 5-6 years. Loads of people still play cs1.6, its the second most played online game on Steam (after CSS).