For what it's worth, my rig so far is...
1 strap per instrument, so each bass, each guitar gets its own strap....
I sold my SR500, kept the strap, and that went on to the SX Hawk in Candy Apple Red, so I have a tan 2.5" Levys Suede strap with a black Celtic ish cross on a candy apple red strat copy. It kind of works due to the maple neck.
My Yamaha (Actually my BILs but in the last year I have played it more than him...) acoustic guitar has the SX poly strap that came with my Ursa 1. It works great for that application, and was a miserable strap for a bass...
My Squier Affinity Jazz, and Ibanez SR480 both have Guild Ballgove leather straps. Nice and long. Those are the only straps I actually have to choke up to get the height out of man land.
My SX Ursa 1, and soon to be SX Ursa 2 (4 and 5 strings respecxtively) hae Perrin basic black leather 2" straps. They came in super rigid. But some massaging with cocounut oil softened them up really nicely.
I have one 2.5" Levys suede strap left over as a spare, it is hunter green and tan that used to be on the SR480, it looks good there, but on that bass the Guild is way more comfortable.
All my straps except the acoustic, are held in place with Grolsch type flip top beer bottle cap gaskets from my local brewers supply.
I never considered a collection of 50 + instruments (where the heck do you store that many basses?), I guess transferrable straps make sense...
In MY circumstances, a strap is in my perspective, part of the instrument. And I have cheap (Perrin basic straps at $9.99) and expensive, relatively speaking (I don't see them for sale anywhere any more, but they were retailing for $65.00 per last year). Absolutely the Guilds are WAY nicer than the Perrins, but the Perrins work great, they just need some break in...