Always loved the box art of aquapolis, Lucia looks so majestic on the front shame I’ll never have that much spare cash to have a box sitting under my bed
I would say there are a few reasons why the prices have escalated so quickly.
Blowoutcards ran out of boxes
A lot of people are opening them and grading cards
Youtubers opening them
People watching youtubers open them and want to be like them
New collectors in the market trying to collect 1 of each
Also people throw crazy prices up on the boxes like legendary collection. Then everyone else decides they need to list for the same crazy price. Not that long ago you could pick up a LC box for $700-$800. Then all of sudden someone listed for $3500 then people thought well at $1500-$2000 I’m getting a good deal. I think now they are selling for $2500. I wouldn’t expect prices to go down anytime soon unless someone discovers a warehouse full and floods the market.
I think the last few went for $1200-$1500 BICBW. I know at least one or two went for that at auction in the past 8 months or so. Maybe some BIN’s went higher, but I think most of those had best offers accepted.
Just search pokemon in the sold listings and sort with value highest. Scroll to the page where the value is around $2500 and I’m pretty sure you will see some LC boxes. It won’t tell you exactly the price but looking at what stuff sold right below and above you can get a good idea.