Which is my point- if you make Wizards squishy, you have to build Fighters to defend them. But it really feels like most players don't want to defend anyone, they just want to swing big weapons and do big damage, lol.
I only have anecdotal evidence for this; maybe what's happening at most tables is that enemies just attack the Fighters no matter what they do- maybe it's because they do tons of damage, maybe it's part of a social contract or gentleman's agreement, maybe it's just because that's how things have always been done, maybe it's because the DM is tired of hearing "Shield! Silvery Barbs!"...I dunno.
I just know that good tanking options exist, but since people have a choice between those and the ability to deal more damage and we know that Champions are way more popular than Cavaliers, it sure seems like the player base has chosen.
Or maybe in their game Protection Fighting Style is enough, even though it's 1/turn, I really don't know, because I don't have the data.
But I still think it's telling that something I think would be a baseline Defender ability, like say, "any creature within 5 feet of you that's hostile to you has disadvantage on attack rolls against targets other than you or another character with this feature. An enemy is immune to this effect if it can't see or hear you or if it can't be frightened", is not only one choice out of several, it inexplicably isn't available until 14th level, lol.