Without a crystal ball it is really hard to know for sure if we would have more people powering up as a result of this change. We do know a lot of people are powering down now and always will be regardless of this change. We need more reasons to encourage being powered up in my opinion.

I think it is pretty clear this change would encourage staying powered up, just as it would encourage new powering up. For pretty much the same reasons: If you have powered up coins and have to wait 13 weeks (a crypto lifetime as you put it) until you get them unlocked, you are more likely to start powering them down now than if you only have to wait 4 weeks (or just one week for 25%).

What we don't know are numbers, but as you say we have enough anecdotal evidence from real people to believe it would make some difference.