No, he's talking about an anti-slippery slope. It would be a good idea.

they aren't charging for the first 2 new demigods, i don't know about later though

And I feel like it was mentioned that they were going to eventually release micro expansions, or some kind of expansions later on

and I agree with innociv. There is a momentum to the game, and being able to rebuild will only slow the game down. The game is supposed to be quick.

are micro expansions a sign that sins didn't do ok, cuz I heard otherwise...

Sins did fine.  They delivered close to a year of free updates after release on that game too.  The expansions are adding elements of gameplay you don't see in vanilla like diplomacy, starbases, etc..

I think what happens is that even with a long tail games like these can't continue to be updated with meaningful content indefinitately unless the devs are getting some sort of compensation. 

Of course, Steam has figured out a pretty nifty way of making the tail longer with big updates + Free Weekends.  Actually, they can give games that had no sales in the first place new life...Might want to take a page out of that book, Impulse..