He says himself his game needs a lot of maintaining ie practicing. Think he's got 5 kids now and went from likely living hand to mouth to being comfortable financially in a very short frame of time relatively speaking. Likely has more money in the bank now than he thought he would earn over his lifetime as recently as 5 years ago.
He probably gets bursts of motivation but when hit with a setback easily falls into "happy with my lot" mode rather than really having the drive to run through brick walls. Much like Gary Anderson in the last few years in my opinion.
Cross is young enough that he might only get close to what he was when money becomes a need (to sustain new life as opposed to real need) rather than an addition to the pile which it probably currently is. Looks like Aidy Lewis has reached/is reaching that point to me and he has new levels of being proper motivated for the first time in a long while after a few years of seemingly happily going through the motions.