I think so, but durability is not really a teachable thing, in many ways.
I suppose better workout regimes and prep can improve the odds of not getting hurt, but I feel like the risk is still high on these two.
Whitlock did change is winter regime, and Houck has started 42 games in his career, but I would not bet the over on 150 IP for either of them. (I hope they both prove me wrong!)
When you say it's gonna happen now
When exactly do you mean?
Based on what we've seen all over MLB, you are right to have doubts that those two--or even any of the other 3 starters--will make it to 150 innings.
But, heck, it's early April. Cherry blossoms still bloom around the Tidal Basin in DC. The Sox could well arrive back at the Fens with decent spring weather. Five Sox starters had terrific first starts to the season. The June swoon might not happen.