I’ve played sod since phase 1 and never spent any money on it beyond my $15 sub which also lets me play anniversary, cata, and retail.
I’ve played cata for a bit in ST phase and have recently started leveling up a new character. I’ve bought the deluxe mop pre-order, a boost, and probably 3 wow tokens on cata. Majority of my sod guild has started playing cata and also purchased tokens and character/race/faction changes.
It’s obvious why they want sod players to go to mop and do not care if you actually experience the full new sod raid.