Unfortunately, you make a valid point. As long as the box office money keeps flowing in, the powers that be (who have no heart about the characters/property and look at it from a business point of view) will be happy with Bay until the cash cow dries up.
After ROTF, I'm inclined to think of any subsequent sequels similar to the crappy Police Academy series, with hokey plotlines mixed with stupid T & A and corny jokes until thank god the thing died.
If Transformers goes this way, the big movie bigwigs will leave the property at the side of the road like roadkill and move onto the next big licence to milk.
The problem is will there be a reboot/remake down the line? I know the movie isn't really catering for the old fans, but for the general movie going audience so the answer may be no.
However, when you compare Transformers to something like Batman or Superman which has 60+ years of history and is pretty much universal for all generations, I don't see another Transformers movie when the next one completely tanks it and the studio execs lose money on it.
You look at how Batman and Robin was completely abysmal at the box office and horrific to watch, thanks to the script, casting and campy direction of Joel Schumacher. It took a couple of years but the studio execs and DC comics were always going to do another Batman movie.
The comic book fan and movie audience response to that steaming pile of crap made them rethink their approach and so they abandoned that franchise to start anew.
They realised they had to get back to the basics and the heart of the character, mythos and go back to the drawing board.
The reboot they did and the results they got speak for themselves. They got a fantastic cast, a proven writer in David Goyer and a great director in Christopher Nolan and they used the wealth of history and stories to make a great movie.
With Transformers I don't see that happening but I hope I'm wrong.
George Lucas who gave us Jar Jar Binks? We already got a taste in ROTF with the Twins, do we really need more?