According to that chart it takes $19,355 just to get from VIP level 12 to 13 by itself. Getting from VIP level 11 to 12 is what costs $10K, getting from VIP level 8 to 12 costs $19,621. It takes a total of $38,976 of in game purchases to go from VIP level 8 to 13.
In this video from March 30, 2018 it seems the new VIP features were very recently released and this guy talks about 'some previous purchases being applied to your new VIP level', so this would be around when the new VIP level cap was released. This guy is VIP level 7 in this video.
So now we have a nice timeline. It has been about 22 months since the new VIP level cap was released. This would average out to Phil spending $1,771.64 per month on WWE Champions from April 2018 through today, or $442.91 per week, or $63.27 per day, if you believe this is Phil as I do. If he was spending in splurges when he was flush with cash or an event was happening as seems to be the case the routine money dumps into the game would be lower with various spikes of splurge spending.
ETA: Maybe Kathy is actually helping out with bills and the extra money she's giving him is going schtraight towards half-naked hairy pixel-men. This would explain why her 2nd income isn't helping them at all, and Phil says he's only been making minimum payments on his credit card debt and loans and getting threats to send him into collections.