Personally, after 50, I simply started to see a diminishing need to craft regular items out of the log to begin with. You don't have too very many options at lower levels for exp gains, so you're somewhat stuck stockpiling and crafting. And obviously it's good to have stuff on hand for quest crafting. Maybe a few items for leves. But after a while, I just found myself mostly leveling through moogles. And now the Ishgard restoration is available in those mid-level ranges. And if you're advancing MSQ faster than your crafters, you'll get Custom deliveries available in that range.

By the time I hit Stormblood content earlier this year, I was all but done collecting materials for anything. The quests start using specially provided materials. Even the gatherer quests don't have you collecting regular stuff I don't think. There's just not a great deal of needing to craft any regular thing in those mid levels. And, if you're just wanting to craft for profit, you still don't need a massive stockpile of everything for that, just a handful of things for the most profitable items you'll craft.

I wouldn't call myself a serious dedicated crafter, tho, clearly. So my goals might not really line up with any that would strongly benefit from inventory expansion. Sure, more space would be great. But also, I've been realizing how little I've accessed my stockpile retainer lately.