This seems to be the popular opinion these days, but I'm a firm believer in the opposite. A reboot almost certainly would have been a pre-1986 inspired cast coming to Earth yet again, with the Autobots befriending a young human and the Decepticons trying to destroy Earth and attain a source of Energon. Transformers is more than just Autobots vs. Decepticons coming to Earth and fighting to destroy or protect humanity. It's Quintessons. It's Junkions. It's Beast Wars or Beast Machines. It's the Cybertronian Empire. It's human-Transformer conflicts. It's alien bounty hunters scouring the universe for their unfortunate Autobot or Decepticon quarry. It's humans experimenting with Cybertronian technology and building their own Transformers. It's Unicron and his heralds sowing the seeds of chaos and destruction. It's even more than all of these things. Continuing after DotM was the best shot at getting some of these things, and we got some of them. Rebooting after DotM just would have reinforced the popular purist position that Transformers should stay in this narrow comfort zone and that adventures can't be had without many of the more popular robots in the brand.