To be entirely fair, and I feel you there a lot: This is a pure ‘you’ problem actually.
Yes, it’s fun to have limitations, albeit those limitations for you (and me to note that) are playing around a non-common premise. Hoarding tendencies give more value to an item then it actually has, seeing more potential and value in things then they actually have.
Not only have the majority of items - we both - collect early on in a cycle exactly no value (as represented by the market as well) but also only take up space. Planning for ‘we might do it’ circumstances which never actually happen. Also the amount of duplicates which could be good are higher then needed, rather then going ‘one by one’ the premise turns into collecting a vast variety since ‘something will fit sooner or later’.
Collecting in a efficient way with limited space hence does 1 of 2 things… either enforcing a ‘check’ personally to re-evaluate items… or frustration, it can go either way and is purely a flavor aspect there.
But the limited stash space in itself is a arbitrary limitation without meaning as we’ve already picked up the items and gone through the whole decision-making and character-space limitation aspect, stash-tab limitations solely enforce a secondary decision-making process.
As said, with a single character you’ll never need more then 5 tabs… actually you won’t need more then the basic tabs given, without paying for a single one. Anything more is either our personal proclivity to stash more then needed… or for people without in-depth itemization knowledge a lack of knowledge to discern the actual value.