I do plan to buy some more SPS if the prices stay at this level or go lower by rotating some of the other assets into them like sold reward cards, vouchers, ...

Eventually all value should flow into SPS and als everything stands or falls with it the way it is set up. Right now from playing and staking I earn somewhere between 700 and 1000 SPS naturally, so there is no realistic way for me to reach 500k without actively buying some.