Why are you so convinced they're trying to rip you off? What do you know about the economics of monitor production? Right.
27" 1080p 60hz £160
https://www.overclockers.co.uk/showproduct.php?prodid=MO-083-BQ&groupid=17&catid=1120
27" 1080p 144hz £260
https://www.overclockers.co.uk/showproduct.php?prodid=MO-121-IY&groupid=17&catid=1120
28" 4k £260
https://www.overclockers.co.uk/showproduct.php?prodid=MO-076-DE&groupid=17&catid=1120
27" 1440p 60hz £270
https://www.overclockers.co.uk/showproduct.php?prodid=MO-070-AC&groupid=17&catid=1120
27" 1440p 144hz £630 (now, £700 at launch)
https://www.overclockers.co.uk/showproduct.php?prodid=MO-070-AS&groupid=17&catid=948
Now try and think, resolution upgrade costs £100, doubling refresh rate costs £100, having both together = £540 increase in cost for a £700 launch price. You have to be plain daft to think they are doing anything other than ripping you off. Even at that price sales weren't great because it was dropped constantly everywhere within a few months to £550-650 price range in sales to get them shifted.
Acer now have a basically identical spec(non g-sync version) monitor that goes frequently around the £370 mark. 3 years ago companies were making panels and scalers that were good enough to be overclocked to 120hz but monitor makers were busy trying to sell everyone 60hz versions so they could later sell them another panel with 120hz, why sell one monitor when you can sell someone two.
The panels and scalers were without even intentional trying to... good enough to support these rates YEARS ago at less than half the price they suddenly started trying to sell these latest versions. Also yes, I know likely a lot more about monitor production than you think I do and I would presume a lot more than you do.
Monitor makers have been dragging their heels for years and years because ultimately if they started selling 1440p 120hz+ panels 3 years ago at good prices... what would they sell today? 120hz is better for ALL users of screens, people who game, people who browse the web and never touch a game. Every single new resolution now is trickle fed specifically going after the premium gaming features and charging the earth for what is now very old and simple technology.
The equivalent of the monitor industry would be Nvidia/AMD launching the next gen 14nm cards with a bunch of current things missing. Double the shaders of current cards(increasing res) but remove things like DX11 support, remove g-sync/freesync support. Still having the high cost, then let those cards get cheaper and sell a 'new' part by adding basically the same spec card but it now supports DX11, then sell a new card with both DX11 and *sync.
We went to 120hz with 1080p panels, 1440p should be 120hz almost straight away... I mean 4k panels coming with 30hz a lot of the time, it's laughable.
Monitor companies push one spec forward but take three steps back, then charge you more again for each 'new' (but actually really old and standard) feature again.
Resolution is the frankly biggest problem in terms of production and yields. Pixel density is the 'hard' part of the monitor making industry, scalers are a joke, you're talking about $5 chips that if you want a really fancy one you're doubling the cost to $10, a small pcb, simple electronics. The complexity and cost comes from panel production. The technology to make pixels that can refresh at 120hz or more is done and dusted technology, a 1440p panel merely has more of them. There is no technology barrier in making a 1440p panel able to operate at 120-144hz as opposed toa 1080p panel, it's the exact same technology. The cost is in producing the panels which higer pixel density or size increases production costs.