Wrong, other structures can reenter
Context James, context. 
And in this context the key words are "reusable," "orbital" and "velocity."
Which structures did you have in mind that a)Reached orbital velocity and b) Can be reused afterward?
Any of the Apollo, Gemini or Dragon capsules.
Fair point.

I fooled myself by thinking only in terms of vehicle that included most of the hardware to get to orbit IE engines, even if it didn't have the propellant.
To do that with something like those shapes we'd be looking at one of the Bono designs of the 60's or SERV or the candidates for the SRT programme (that produced DC-X) in the late 80's.
Considering what happened to Columbia, I'm not sure why you're advocating for wings. "It's always been done that way" is rarely a good argument, especially if it's only ever been done once. Twice if you want to count the X-37, but Gemini 2 did that first.
X37b has launched 4 times as a design and you forgot Buran.
Actually what I "advocate" is lowering the $/lb cost of access to space in reasonably sized lumps of lift.
something more like 2x the price of a Business class ticket (so you make a reasonable profit) between 2 destinations 1/2 round the world apart (roughly the "energy cost" to orbit) where you don't have to buy the whole planes seats to get that price.

I'm not a fan of the STS architecture but it did demonstrate
a) A vehicle (the orbiter) could go to and come back from orbit without making radical structural changes (like throwing away a support module).
b) A winged vehicle could do that without needing to be protected inside a shroud to avoid disturbing the rest of the launch architecture too severely IE like the X37b. TBF Buran also demonstrated that on its single flight.
Yes SX have demonstrated recovery and reuse of the first stage.
Yes that's a huge practical achievement. I think that should shift everyone's thinking about what's possible with a VTO TSTO architecture. Time will tell if it actually does.

But conceptually it's no more than recovering the SRB's and refurbishing them.

SX are going to have a go at recovering the upper stage intact on the FH launch. But SX has bauked at doing this once already in 2014 and we don't really have a clue exactly why. I repeat "It's uneconomic" is an effect, not a cause.