My $0.02 worth of modest proposal:
Change the substitution rules and make say, four or five players play both offense and defense. They can still get substituted in & out, but it would have to be over a period of time.
Then you’d see a different type of athlete instead of a behemoth.
As I said, just my $0.02.
Your 2¢ worth makes sense. One platoon football as in the late 50’s and early 60’s would cut scholarships thus costs. Players would have to be fundamentally sound and well conditioned. Of course with the concussion issue and the feminization effort against the American male, football will likely vanish or be p!aged under drastically different rules in 30 years.