Um this is kinda ridiculous. For them to continue that now just isn't logical. It's been too long man. Also where else are they going to go with it anyway? Design more HMS or what?
Also most of your reasons are wrong...
1) How would they make twice as much money?
2) What are you talking about? G Rev didn't end on a cliffhanger.
3) Everyone meaning who? We have so few people here who buy plastics...
4) What loose ends?! The tournament ended and then they fought BEGA. I think that was pretty complete. Just because they didn't start a new season doesn't mean that's a loose end. It's just the end.
5) What? Despite what you think I doubt the people who watched the old show would buy the new toys... They're in their teens and twenties now. As if they have time for that. Also when they make toys the aim them for general. Aiming at one limited market is a recipe for disaster.