This entire discussion could be solved in one simple way: Pay pilots by their length of service/seniority instead of the size of the plane. There would then be fewer difficult, complicated, loophole-filled “scope” clauses to fret about.
If the company wants to buy RJs? OK. If they want to buy A-380s? OK. Company pilots will fly them at the same pay scale. Slow growth/slower upgrades? Not OK, but much less painful as step pay increases would come at the x year point instead of an aircraft upgrade. Same for the age 65 debate. Everyone could bid/fly the lifestyle they prefer and can hold—all with the same pay. The company has less cost in training because folks don’t have to change planes to make more money.
It’s a win/win/win situation