Noone is suggesting to REPLACE raids with small-group or solo progression content. We suggest that Blizzard ADD that type of content, while leaving raids where they are.
This way those who raid because they enjoy raids would be able to continue raiding, no? The rewards and the amount of skill required would be the same, that's the goal. Raids would have an additional burden to overcome in that they would require an additional effort to organize. But they would also have a huge additional reward which you are talking about above, which is the whole reason many raiders raid in the first place - working shoulder to shoulder with others, feeling that you accomplished something together.
Are you saying raiders need those extra ilvls because if they don't get them, they won't group as the entire working together thing isn't so valuable to many or even most? Because I know that some would stop raiding and some would continue raiding, the point is that those who'd prefer non-raid progression to raids are perhaps genuinely better suited by non-raid progression and those who'd continue raiding are better suited by raids. It's a win-win.