Would you rent a $14,000 DAC for $75 per day?

No.

I think this idea has potential, If you’re okay with possible damage, loss and theft, start with the Tambaqui and see what happens. I'm guessing there would be more interest in auditioning speakers. But they don’t ship well.

If you’re a serial entrepreneur, this could be a fun challenge. A lot of risk and headaches for the ROI. Maybe pay a consultant’s fee to a high-end camera rental manager to learn about the pitfalls.

I think you'd be better off setting up a space with said equipment and allowing persons to rent the space.  For instance, I would use a high-fidelity DAC to transfer CD recordings to tape.  Or let's say someone wanted to bring in their collection of CD's and rip them all to a portable storage media.  There are plenty of use-cases one may consider.

But loaning your equipment out by way of logistics?  Just sounds like a great way to break something, lose something, get back a non-working version of what you had, etc.

I once thought about this as a business model but so many scams out there, considerations about equipment getting returned in working condition, etc. 

I kind of wish there was enough interest in audio that say, a music museum could pop up with listening rooms of different grades of equipment to try, have demonstrated, etc., along with exploring music of all known genres to further increase interest.  Would be a great place to visit. 

My fantasy anyhow. 

No.