I disagree and susepct costs would decrease or at least stay at a sustainable level.
Currently the restrictions on design, cylinders, materials, fuel flow, MUG and other hybrid components pretty much dictate 90% of the engine and that leaves the manufacturers 10% to hone to the nth degree which Mercedes spent 100's of millions on getting about right prior to the tokens coming with Ferrari, Honda and Renault now trying to spend millions more to catch up but as they're mostly restricted to their original design philosephy (within the regulations) its a money pit trying to hone what they have to the nth degree to catch up.
I'd image some basic rules such as 100KG fuel per race and 1 engine per event would not only open up a world of new possabilties as no doubt each manufacturer would go different routes in terms of cylinders, MUG, turbo, supercharger, and anything else they can dream up as each resulting power unit would differ, they're would less of a money pit as you don't have to spend £10's of millions honing a good design that works.
As a bonus, new hybrid technology that can be surplanted to road cars will come on leaps and bounds as whose to say the current formula with 1.6L, 4 pots, MUG et al is the most efficient way to make use of 100KG's of fuel?