Definitely not. One of the coolest things about Monster Hunter, as a franchise, is that it's possibly the only mega-successful franchise in the traditional video game industry that hasn't felt the need to ramp up production value with every new entry, "just because they can get away with it", until the series is in a position where it needs perpetual, continual sales growth in order to be financially viable. I think it would be horrible to leave the traditional console gaming industry bereft of the one example of successful smart, sustainable business practices.
And beyond that, the lower fidelity simply allows more content to be produced. If you're a fan of Monster Hunter, I have absolutely no idea why you'd want the franchise to go down the route of producing less and less, all in the name of making everything prettier.