A coworker and I were just talking about the lack of a 27-inch iMac yesterday. He's on an older intel 27" iMac that is getting long in the tooth and we were discussing what would replace it. A Macbook Pro + Studio display? Probably, but that's really expensive and he doesn't actually have a need for a laptop. A Mac Studio + Studio display? Even more expensive and doesn't net him anything. A 27-inch (or 30-inch) iMac would be the right product for him. Probably for me too!
Again folks are presuming that Apple is going to price this at the old 'mainstream' 27" model prices. That isn't necessarily the case ( especially if substantively crank up the screen size).
If 27" iMac is older than 2017 and is sufficient to get stuff done haven't bought a 2020 model when had the chance, then Mini and Mini Pro are also possible options.
For the $1700-2,000 much older iMac 27 from 3-4 generations ago the Mini is no where near as crippled as it was in 2014 or 2018. The Mac Studio is Apple's 'direct substitute' answer for stuff that was more so at the top of the iMac 27" BTO configurations, but the Mini Pro is covering that lower end for many and the Mini covers for a few more.
if just want to do normal 'office apps' + email + web browser + edit video/pictures from camera/phone + misc apps. the Mini can work fine. That is probably taking a decent chunk out of what used to be "herded into an iMac" sales.