I thought that the reason why steem_per_mvests is increasing, is because every day new STEEM is created for:

• rewards pool for content creators (today that is 44,825 STEEM)
• witness/mining rewards
• liquidity rewards (currently disabled)

To counter all this inflation, 90% of the inflation is offset by growing steem-mvest ratio. So the dilution to the stakeholders is only 10% of whatever yearly inflation rate for Steem is (upto max 50%).

Thus, you could not live off your SP while powering down. You would have to put that SP to work via curation to offset for dilution.

Please anyone correct me if I'm wrong.