I've been looking at ESP guitars for some years now and I've always wondered why do some of there lower end models have Neck-Thru construction and upper models have Bolt-on necks for pretty much the same guitar. Woudlnt Neck-thru be the more expensive option?
It probably has to do with the market preference. A lot of the younger crowd who can afford the cheaper models mostly want neck-through due to what they believe is better. Most of the higher end ESP's have Neck-through, but some of the Artist series are Bolt-on as many artists prefer Bolt-on still... That and it's easier to replace the neck on tour than have a new guitar built XD
From what i've seen, in standards of guitar it goes bolt-on for the cheaper ones, then set-neck then finally neck-thru for the more expensive one. The thing that annoys me with esp's are when they have signature models, say Michael Amott and he has for this year a couple of different coloured guitars, then they have practically the exact guitars called 600, with only a couple of differences i've seen - set-neck, and different tuners.

But i've never seen what you have seen, with bolt-on being for the more expensive guitars, unless it's a signature model where that's the artists preference, maybe.
tbh if a guitar is bolt-on or set neck makes very little difference to a guitar, especially if everything else on the guitar is top notch

most professionals probably prefer the ease of replacing a bolt-on neck if it gets damaged over the slight difference a set neck would make.

waiting a few weeks for a new guitar to arrive can be a very long time on a tour