I love this topic.
I've owned and played to death the same bass for 20 years (only one bass in 20 years, my lovely Yamaha BB1600) not even thinking for a moment that the problems I had with finger stretching and technique were due to the 35" scale and the 20mm string spacing.
Two years ago I discovered there was a whole universe of different instruments which I had always been aware of but had never been able to try out (living in South Italy did not help, also).
In these two years I've bought and sold more basses thank I could think of.
Many of them have been sold two days after I have received them because they simply did not click.
Now I own a Zon and a jazz RI62 two great basses with a perfect sound. much more expensive than my Yamaha BB1600 but I still cannot link to any them.
The Yamaha feels like a log in my hands nowadays and I could not play it anymore, but...
I would never order a custom bass.
All I can do, living in nowhereland, is to buy basses which can be resold quickly if I don't like them. No sense to order a custom Roscoe if the resale value will be (if I'm lucky) one third of what I paid for it.
The Fender gives me the perfect sound for some music. The Zon has a modern sound which is perfect for other music.
------------------
About custom instruments low price I have my idea :
When someone orders a custom XYZ is prepared to shed 3000£ for it.
If he should not like the bass, I assume he should be prepared to lose let's say 200 or 300£ to resell it.
Same thing for the second owner, which would lose 200£ reselling it (we're not talking of basses with a strong resale value), and so on, until the bass reaches its used market value, which is the standard price similar basses has been sold for.