Never mind how strong the thing itself is, that joint is basically impossible to engineer so that the wheel can't rotate side to side. That is, rotate on an axis it's not supposed to. Sure, you can prevent an (essentially) round thing from rotating with a pipe clamp, but now try to do that while allowing freedom lengthwise.

That wheels are round and not pipes help a bit, there's some lever purchase you get from the radius but in general, nope. You're still sitting at the short end of the lever.

Diamond frames with spoked wheels are literally the optimal solution to the problem the rest is compromise (e.g. having no top bar for comfort) or overengineering.