Prog Archive standards of progressive are so lenient I wouldn't normally use their criteria. Every album I own with exception to about 20 country/folk albums, and 50 or so various orchestral recordings.
I sell my albums if they're not rare or brilliant; so I may have had in my hands at one point or another around 3 thousand, because i will buy about 5 or 6 albums a week and sell most of them back. I've kept a lot - so in my house I probably have about 500.
In those 500 are my Anglagards, Bancos, Return to Forever, HoyryKone, Sloche albums - things either hard to find or are brilliant. Proudly on the mantle is the original EP print of Anglagard - Hybris.
My point is...size doesn't count - especially if you have a bunch of Opeth / Porcupine Tree/ Devin Townsend nonsense cluttering your shelves....content does.