It's a strange situation. If earning from SPS turns out to be a disappointment (nobody really knows how much SPS the average player will earn) I would be more inclined to buy even though the directly might lead to a lot of players dropping out of the game selling their assets. If everyone turns out to earn crazy amounts of SPS for good earning I would be more likely to dump what I earn as it won't be sustainable while at the same time this likely would lead to a big onboarding of new players that come in for the $$$.
Regardless, It's going to be interesting to see how exactly things will play out.