Dodge makes a V8, proudly advertised in every one of their performance cars.
Nissan/Infiniti makes a V8, and all of their race cars (GT, Supercars) run a V8.
Audi/VW, same thing.
Hyundai/Kia, same thing.
So is our current engine formula not relevant to any of those brands? Would a different engine be the big draw to get them all to sign up? The ONLY potential manufacturer that doesn't have a V8 is Honda. One POTENTIAL manufacturer. And we're supposed to change the landscape for them?
IF that's the only thing that is stopping them from joining (it isn't) and IF our current three manufacturers are OK with developing a new platform to appease one new competitor (they aren't) and IF it could be done with cost control in mind (it can't) then sure, let's change everything. Maybe I'm wrong, maybe we can get everyone on the same page and develop a non-V8 engine that makes everyone happy (including two new manufacturers) and maybe it can be done without costs skyrocketing. I'll believe it when I see it.
Besides, right now we have more manufacturers than we did in the boom period of the 90's. There were a half dozen Pontiacs in the field but it was basically GM vs Ford. We don't NEED more manufacturers, we just need to keep our current three happy and look to add one or two more who are willing to join without us changing everything for them.