I don’t think anyone is arguing that working on a laptop on the kitchen table is suitable long term, in my home office I have a sit/stand desk, quality large monitor and wireless keyboard and mouse with I just need to make one connection to via usb-c to my MacBook and I have power, hdmi and multiple usbs incl my backup hdd. Laptop also acts as a second screen. I have a similar setup at work so if I’m at home or at work all I need is my MacBook but I can also work anywhere else too, meeting, trips etc or bring the laptop down in the evening for browsing and personal stuff on the couch.
I’d argue it’s a better setup than having a desktop.
Don't get me wrong, I'm not saying that desktops will replace laptops - I'm just saying that laptops won't replace desktops (which people have been saying for the past 20 years). There will be people who will get by with just a laptop. Others will have a desktop and laptop, others again will have just a desktop.