I think what this solidifies is that the Chiefs will at least be 'good' for as long as Mahomes is healthy and Reid wants to coach. This should be an extended period of excellence. I don't think they can count on going to multiple Super Bowls though. Realistically, they should be coming off back to back SB wins if that idiot Dee Ford learned to look at the line of scrimmage.
Let's not forget the possibility of them keeping Bienemy in the fold to take over when Reid is done. For all we know, breh might have the offensive genius too, and people are downplaying it just because Reid is so hands on.
Overall, I like the deal. Especially since it seemed like there was mutual interest in getting it done, unlike many other deals. I'm also holding on to the idea that this deal gets reworked in a few years when they feel the squeeze for cap space.