This was my take away as well.
It makes me wonder if there was a sweet spot around 2010 when prices were lower in comparison to income or inflation. eg. If the cost of space marines remained stagnant and it's only the last few years they bumped the price.
Nah. It's really just the past few years that GW has been publicly announcing their price increases on warcom(with averages running 5-10% and they started getting fucked in freight cost increases in I believe it was 2022?) but they've been happening the entire time(just only informing retailers rather than customers directly). Sometimes not annually(and then seeing larger increases to make up for the years they didn't bump the prices), and sometimes on characters normally sold at lower volume to I guess offset things like 10 packs of space marines packaged for Horus Heresy, etc. And of course factor this in with how even more people are online and communicating with eachother(complaining really, not that it isn't justified) making it easier to spot price hikes in places around the globe.
2011 had price increases around mostly 10-25%
Here's icv2 discussing price increases(including some apparently up to 70% but averaging 20%) back in fall 2008(they don't show individual breakdowns unfortunately)
This site has a lot of archives of their old print catalogs. Around 2005 I believe it was they stopped printing prices in them but you can still follow the price increases over time during the 90s pretty easily(with blister packs for non characters being some of the worst value, as well as getting random sculpts for buying individual infantry via mail order sometimes)
Here's a forum thread discussing imminent price hikes(and then complaints about it) back in 2004
Here's a working archive.org pull from their UK webstore back in 2007 where you can browse prices as well. There's some weird pricing especially on their discount boxes for shit like the space marine megaforce being 100 pounds with 1 character, basically 30 infantry, a razorback, dreadnought, and predator. But then the 105 pound starter set only has 25 infantry and a rhino, but bundles in some bullshit like a rattle can of black paint, a stupid how to paint book, and their overpriced tool "kit".
So yeah, shit's always been expensive, and GW likes to keep their margins absurdly high(hence having the cash on hand to be building new factories rather than taking on debt for it, which is a good business move just not great for consumers).
The only models I own are the Necrons out of the Necrons vs AdMechs battle box I split with a friend back in 2019. I thought about getting more, so I looked at the 'start collecting' set because there was a Games Workshop store right down the street from me. It was $75 for 23 models. To expensive, so I passed. A couple months ago I popped back in just to see how much more expensive everything got. They don't have the start collecting sets anymore, instead they have something called 'combat patrol'. The Necron set comes with 19 models, but costs $170. More than twice the price for fewer models.
There was also a smaller start collecting as well that they released later with only 17 models(one was a triarch stalker) in it for $90, Then the original combat patrol at 15 models(1 being a doomscythe for some reason) at I want to say $130? Then the current one with "19 models"(fucking lie, 3 of them are just scarabs on the sprue with warrirors, but at least they're a unit. And then the plasmacyte for the skorpek destroyers which is just a fucking token now) for $170. With the combat patrol "game mode" being an unbalanced dumpster fire.