Remember attunement slots too. If you are a low STR character that doesn't need it much then you will use your attunement slot for something more beneficial.
5 PC party. 3 attunement slots each. 15 total attunement slots. 20 levels.
How many attunement items do you think most DMs will hand out compared to non-attunment items?
How many total items in 20 levels?
I suspect that the vast majority of attunement items will be sucked up in most groups and that most PCs will have attunement slots open for a REAL long time. Most games typically do not even get past level 14 or so.
Attunement number of items is a restriction, but one that will very rarely come into play. For it to do so, one player will own 4 such items and have to decide which one to give up. I don't know of any groups that will often give one player 4 such items before everyone else has 2. So, typically 12 attunement items before it becomes an issue.