You do? I only have two on my main and neither one is full.
You are not everyone. On my main cargo space is often an issue. I'm certainly not going to toss out gear once I throw MK-9 kits in it, I can tell you that much. It's great that people suggest tossing what you don't need and can get through collections, but that's just not possible with all items.
Toys, things for sale, mats, items that don't stack, etc, etc. It can all add up. If it's feasible no reason that it shouldn't be implemented. If not, then so be it. That said, your experience is not that of everyone else, and to make an offhand comment as though it is comes across as foolish.