Yup, I think that too. She's not a "catallogue" artist (yet), even if her rescent albums were just excuse to go on a tour, I guess this is her goal: stay relevant, go on a big tour, maybe do a side project here and there (films, merchadnise, or such). And I think we have to wait for any major "deluxe" reissues with bonus tracks, compilations, archive material, boxes, untill she does not have a current work to sell.
As for Blond Ambition or Re-Invention tours - I guess M/her management can block releases for copyright resons. Also, I don't see why Warner would promote an artist who works for different company now. They may issue a budget compilations when she's releasing her own project (like they did recently with album boxes), but they won't release now anything ground breaking.