Level 16 atm. I don't think it's a big deal. Many players (including myself, usually) tend to optimize play, but it actually isn't required even with current level of scaling. Our 4 player group doesn't buy much items, so we have always lower level loot and we still win all fights (some deaths, but almost always due to misplays).
See the scaling system as a difficulty tool. If you buy items every level it is easier, otherwise harder.
