I reckon their demographic is:
- one third aspiring fusion shred masters
- one third metal dudes who can't afford a Dingwall but want to tune to low F#
- one third a bit of both
( I do own a 7 string bass, and would fall into the last third fwiw).
There is also a 34" scale 4 string https://www.thomann.de/gb/harley_benton_bz_4000_ii_nt.htm
Probably not one for the purists, but a 35" scale neck through 7 string for just over £500 new. Looks pretty cool, and while the headstock is still a bit clunky looking the string pull looks sensible.
https://www.thomann.de/gb/harley_benton_bz_7000_ii_nt.htm
I know you don't want to be a shredder but there's probably someone selling an Ibanez RG somewhere in your neighborhood, which tend to have very fast (shallow and quite flat) neck profiles.
My experience of Elixirs suggests that they probably will not protect you from the metal 100%, they tend to flake a little, especially if you're playing a lot.
I have a fretless 5 string which is pretty good. I upgraded the pickups to the higher spec version since they came up used but frankly it didn't make much difference.
It reads to me like the 40th anniversary thing is just coincidental timing, and I'd guess Fender might be more impacted as they often make up a large proportion of shop stock compared to other brands.
When I played with a band who tuned to D standard I found it much easier to play a 5 string in standard BEADG. That was better than keeping my bass down a tone and transposing when playing with people in standard tuning.
No idea about the handedness debate but IME there is very little about age-group classical ensembles that is representative of the wider population -- you're largely selecting for who showed more "promise" at a very young age, and children with more affluent parents are at a massive advantage. Not sure if that makes it more likely that left-handed children are more able to adapt at that age or are filtered out.
YMMV, but if having it around is going to make you feel guilty, or you don't have the time/means to get it to a standard you're happy with, I wouldn't feel bad about stripping it for parts and chalking it up to experience.