A wizard still needs items for saving throw bonuses.But there is a problem with this in that it affects only some classes.
A wizard can play from levels 1-20 without ever needing a single magic item.
The fighter cannot.
That's the issue.
5e is modelled after 2e and 3e that both used magic items. So it must have magic items bonuses factored in.
However since 5e's math is much lower, it is trivial for a DM to replace a magic item with a nonmagical masterwork item or another boon like a feat, bastion training, action points, or something.