There is absolutely a market for these.

The S-works Venge you include as an example was an $8,000+ bike brand new. At $3,650, I'd jump all over this used vs a new Ultegra Tarmac with base wheels.

I bought my first carbon bike used. Paid $2,000 for a 3 year old Marin Stelvio with full Dura Ace. At that time, anything new with full Dura Ace was $5,500.

Can be tough to fathom when we're bartering perfectly good classics for <$500 but the youngsters are paying for speed.