hmmm, Taraz - you amaze with such ideas! :)
basically what you propose here is ... to make the existing system more HYIP than it already is. LOL
(or perhaps more like into Lending platform, if someone rather prefers it... or High Yield Corporate bonds aka "Junk Bonds")
well, at least it's good that words "Investment" and "Stakes" are being used more frequently - it helps to reflect the actual meaning and purpose of this platform (aka "Ecosystem") and clears out the confusions.

however it contradicts the idea of "improving content". because content is not a main goal / aim / focus / concern / interest / objective here. it is "PASSIVE INCOME" or dividends / derivatives. why people would bother to care about content at all (or its quality) - if they don't even need / have to open that particular post to "Upvote" / "Curate" it? even those who do not use bots. "Content" is just a ... LINK in the list, a medium between the act of pressing that "Upvote" button and then getting the rewards 7 days later. LOL
and "Curation" is merely a ... "discovery" of some potentially profitable Links (which can easily be calculated and estimated by all those factors: reputation, wallet size, number of followers, participation in curation-trails and bots)

come on! system does NOT require and practically doesn't bother with "good" or "bad" content or its "quality" or "indifference / interest" to content. system mainly "concerned" about the generation of many connections as a results of pressing that "upvote" button and about ensuring those "long term capital commitments" (i.e. High Yield corporate bonds). so, yeah - may be in this regard idea of "Lock up stakes" - would get the interest. (although locking capital in form of SP already largely takes care of that) but "improving content" - what for? :)
if it already works well enough and smooth, gives the fat dividends (especially considering compound interests)

main concern of the investors (i.e. stake-holders) would rather be - how to bring in ever newer users who would also invest and then "power up". preferably more and more of such. (so that those who are old investors could cashout their earnings)

but hey, you are always able to stir up some active discussions and debates! :D