I find the question of flywheel motors interesting. For me, it is a no-brainer to have a flywheel, but I can understand LGB not going that way as they were, to a certain extent, in their own little bubble, and did not have manufacturing experience in other scales and gauges. Piko, on the other hand, do have direct manufacturing experience in the smaller gauges, and I don't know why they haven't gone the flywheel route.
Using a double ended motor with twin drives can provide a certain robustness in the drive train, but using a flywheel on the motor relieves a lot of stress on the drive train, and helps with the occasional stutter on dirty track and point frogs. Yes, and while you can use a simple stay-alive when running on DCC, there's no such easy solution for DC.
It wouldn't be that difficult to include a flywheel on a double drive motor - in 00 gauge you have motors with twin flywheels and extended shafts, so it should be achievable in large scale. To my knowledge, of the major manufacturers, it's only Bachmann who have pursued the flywheel motor and, I assume from the original question, MTH as well