Not my experience. My group is now 15th level and none of their magic items give a bonus to hit. We don't run published adventures. However, 5e was explicitly designed to work without magic items and I argue it works best with as little magic as possible.
No, it wasn't. Next was explicitly designed to work assuming no magic items and then without telling anyone that they changed their mind, they designed 5e to no assumptions of having the items you wanted, but you would have approximately certain values.
And we can know that by how Champion Fighters without feats work from levels 11 to 16. Namely, hit points of monsters from 11-16 go up about 45%(16/11), Monster AC rises +1 over that time period and proficiency rises 1 also. The only real improvement to damage for a Champion Fighter is an extra 1 crit chance in those levels at 15th for about an 11% increase in damage. That extra damage is supposed to be from somewhere and surprisingly enough, if you go from a +1 weapon to a +3 weapon, you get a 43% increase in average damage from 11th to 16th.
Coincidentally, if you go to the 'typical campaign' on page 133 of DMG, on average, roughly that is likely to happen in that time period. There's a lack of certainty of it happening, but...
i.e. if you don't have magic items in your campaign, at some point, Champion Fighters are going to feel as if they suck, because they don't do any extra damage without them. Because the system is designed around the idea that they have a boost from magic items.