We can make this what if argument in circles until we're all blue in the face.
At what guaranteed dollar amount do you think he would need to obtain for this holdout to have been worth it? He punted $15mm and a year during his prime, that is the only fact in this equation.
The holdout being worth it wasn't the point. You said you don't think he loves football because he sat out a year, and gave up $15M to do so. My point was that those facts don't mean he doesn't love football. It IS a business, after all. He didn't want to play another year without a long-term guarantee, and the only way he could do that (after he and Pitt missed the deadline) was to not play at all. Now, he will be able to sign a contract that won't force him to do that. He WILL get more than $15M guaranteed in his next contract, so he will make up that money.
With regards to the missed season (he DID NOT hold out) being worth it, we'll never know.
IF you assume he took the $14.5M in 2018, and suffered an injury so catastrophic he never played again, then any contract in excess of $14.5M guaranteed means the missed season was worth it.
IF you assume he suffered a major injury in 2018 but continued his career with major injury concerns, then his next contract would have reflected and maybe contains only $10M in guarantees, than a contract this off-season that is worth more than $24.6M in guarantees made the missed season worth it.
IF you assume he played 2018 and stayed healthy, you have to also assume that Pitt would have used him as they had in the past (i.e.-400+ touches). (That puts his career touches (regular season only) at right around 2000 touches. His value would likely be lower, with another season of insane usage.) But let's assume his contract offers in 2019, after sitting out a year, would be comparable to what his offers would have been after getting 400+ touches in 2018. So, under what circumstances would he make up that $14.5M? He'd have to play longer, obviously. And while it's unrealistic to expect him to get another season at the back end of his career making $14.5M, if his new team doesn't use him at the same rate (400+ touches/year) as Pitt did, it's not unrealistic to expect him to have a bit of a longer career. 400 less touches in 2018 could reasonably result in 1 extra season at the end of his career. Give him $5m for that year (RBs like Bilal Powell & Latavius Murry made $5M in 2018). If he averages 250 touches a year with his new team, instead of 400/year with Pitt, it's not unreasonable to expect he'll play another extra year. Give him anothor $5M for that year. Now the question would be: would he play a 3rd "extra" year at the end of his career? I'd guess no, so he'll likely end up not making as much money as he would have IF he had played 2018, been given the extremely heavy workload Pitt had been giving him, AND not suffered a major injury.
So, it depends on which assumptions you want to make, as to whether you believe his sitting out a year was "worth it" or not.