It's not that connecting speakers is hard with the new iMac (2021, sorry not 2020), but that having anything permanently plugged in will look silly:

https://9to5mac.com/2021/04/20/m1-imac-relocates-the-headpho...

I guess it's only meant for headphones in a pinch, and you are supposed to buy Bluetooth speakers/headphones anyway? But Apple also discontinued the big HomePod that would give the iMac some oomph.

(I often suspect that the new iMac is that primarily meant as cashier machine in clinics, boutiques etc. In that context the design is probably fantastic, but then what is the successor to the iMac G4 line? Maybe everyone just uses laptops for family computers?)