I like and have both styles of guitars, but I found regardless of all the pickup swaps I’ve done, my 25.5” bolt-on guitars still always sound snappier with a sharper attack, all else being roughly equal, but for high end complexity I can agree. I don’t find more low end on set-necks, but maybe more more low mid fatness. In either case for pure low end, no other guitars I’ve tried touches my all rosewood body 1978 Schecter (bolt-on) or early Barlow (all ebony neck and Paduak body, also bolt-on). Both also 25.5”. I’ve had some really heavy Nolrin era LPC’s (they also sounded like furniture to me) and they weren’t on the same level of punch, density to the notes or low end of those 2 guitars (also very heavy though)
I understand that a 25.5” bolt-on is in and of itself generic for metal, but it’s just one piece of the puzzle (that I feel they got right personally). My current 25.5” Bolt-ons all have other specs that I feel sound way more distinctive than any LP I’ve used for metal such as body wood choices (Rosewood, Paduak, Spruce, Western Red Cedar, shellac finish (which I find at least on my guitars results in more 3D complexity than anything I’ve had including even my ‘57 LP Jr, superior to nitro IME) and lastly the pickup like you said ranging from ‘50’s & ‘60’s Gretsch’s, Guild’s, Hofner’s, Hagstrom humbuckers, vintage Bill Lawrence’s, Schallers, Dirty Fingers, vintage Gibson pickups, and some less known modern ones
Of course, boosts, pickups and amps themselves can provide all the attack or treble we need, but still I find in a different way than what a bolt-on 25.5” guitar provides and it also I think is about mixing together all the ingredients/puzzle pieces. For example, with a super tight attack-y amp like a Hermansson or Dino I may even use one of my LP’s to balance it out a bit, but with most other amps being nowhere near as tight/attacky I may go for a bolt-on instead, but some of my current 25.5” bolt-on’s including my mahogany Marchione (and a few others) is so complete in the sound it provides that I am planning to sell my ‘57 LP Jr, ‘64 Epiphone Riviera and a few other heavy hitters. I love a good lp as much as the next guy (I’ve tried my share of real ‘50’s burst LP’s too), but these are just my finding doing lots of comparisons/my homework