Vests are shares in the Steem Power Fund. If a user takes no action on the >Steemit Platform, his/her shares will remain static in quantity, just like >shares in a financial fund.

Your "shares" stay the same, but if more people are joining fund grows bigger and your actual"share" of the fund is diluted. So your SP is diluted if you do nothing and if marketcap does not grow people actually lose money on SP. I think a lot of people do not understand this part.