You've already mentioned 3 of them for starters - Keuchel, Correa, Springer (whom you evidently view as a big loss, and I'd argue the jury is still out on given the length of the contract, not to mention the fact that Tucker made him unnecessary - he's not good in CF anymore).
That statement was made in the context of your statement that, "teams routinely pay bigger money to aging players in the back end of contracts knowing there's a good chance the player's performance will fall off." None of those deals fall into that category - the oldest player at the end of it will be Altuve, at 34, and his AAV is a bargain. But they wouldn't budge on the years for Correa. Springer will be heading into his age 38 season when he's a free agent. Etc. And every single guy you named they extended was younger than Valdez is now - and that's without taking into account the aging of groundball pitchers that we already have covered.
So the question is, is Valdez more like the young guys they extended, or the older guys they didn't want to give longterm deals to? Even at 5/$90 like you propose, is he more likely to be an effective starter at 34, or washed up before he even hits free agency? I don't think "giving him his money" based on what he did last year is smart, and I think the Astros history of NOT doing business that way is a good thing.