I think with Transformer figures becoming more versatile, they've been able to achieve since G2/Beast Wars what the Action Masters were trying to do - make a more action figure style Transformer. Therefore the Action Master idea has become less "necessary" but it does mean we miss out on the stupid fun of bigger playsets and transforming suits/vehicles.

I personally don't have a huge desire for the original Action Masters as they mostly passed me over - I was more interested in the gold box reissues (I was 6/7 and the reissues were the ones being shown in the cartoon). I have a couple of the original AMs and was always a fan of the redecos the club did - Kickback, Jackpot, Krok, etc, and could ultimately be interested in getting the ones that were only ever released as Action Masters (Banzaitron, Charger, Krok, etc), but I have other areas of focus first.

As for whether Hasbro would ever get back to the concept - unfortunately I think we'll only ever see Action Masters as a licensed product at best