Could you make a fretless bass by...
 

...Simply never having new frets put in and wearing the old ones down through wear?

Expensive only in Time! ;)

Typically you wear down the frets in the first few positions much sooner than those in the higher positions. Result: buzz. Let me know how it works out for you wearing down frets 6-20. Get back to me in 50 years.

Note: don't bother, I'll be dead. ;)

even going all-in with this idea and grinding the frets down to nothing has issues; the resulting "lines" of the fret tangs left in the board are way harder than the surrounding wood, and with playing time will "re-emerge" as the wood wears away around them.

Magical Morphing Fretless Bass! :hyper:

Then we wear down the re-emerged frets and presto, fretless again!

Ezmar, have you been drinking? :p

No.

But I've had several late nights lately, which for me is about the same thing. :rolleyes:

:D It may be easier to burn the bass and have bassless frets :D

This man deserves a grant!!

Actually it does work.
The problem is that when you're done,
it looks like you have 20 brass nuts.