IOI manged to release 2 eps in 7 months with members promoting in other groups, they just need better schedule, SM didn't arranged their schedules good enough and they always prioritize everything 127 over anything Dream for Haechan and MK, like any random YouTube show will be prioritized aver any kind Dream schedule, even awards show. A unit with the rest of the members and better individual activities would a worked too.
If their schedules were managed better, they wouldn't end with 25 songs in over 4 years and lots of hiatus, it clearly mismanagememt a big time and SM paying not attention to Dream.
I mean, they were still under contract with their old labels. The girls debuting gugudan still had to prioritise one group over the other. They only did their debut album with the new group and went back to IOI. It was a short term project, and the groups were fixed with no overlaps, unlike NCT. We don't know how it would have played out if IOI was permanent. They didn't have to think long term. There was one sub unit under IOIs brand and they released one song. Stone Music isn't known for great artist development either. Produce groups are usually overworked so I don't think they're a great model for permanent groups.
Don't know what else to say about it. If SM intended everything to be even across the units then they probably wouldn't have put Mark in 3 of them plus SuperM on top of that.
I don't wanna derail here further so you can dm me if you have anything else to say.