I am unable to replicate these findings and I did 3 fresh installs in a VM. For Ref I used US install media but I am in the EU so maybe they are doing this based on region based on my IP address all 3 test where done while online (couldn't be arsed to VPN to the states to test).
(I only have pro license's to hand, maybe its diff with home licenses, EDIT: Just got a home license. I'll test with that for the shits and giggles off it. But honestly, we should be installing pro for people so we have easier control via group policies anyways BRB testing more now i'm back home.)
First test: I installed a fresh copy of Retail Win 10 Pro 1903 downloaded today from https://microsoft.com/en-gb/software-download/windows10iso (Note: unless you fake your UA to be something other than windows it will redirect you to the media creation tool download. Say you are an iphone for example it will happily let you download the raw ISO without the media creation tool) During install it gives me the option to use an offline account in the bottom left [0].
Second test: I installed a fresh copy of Windows 10 Pro 18970 insider build from https://www.microsoft.com/en-us/software-download/windowsins... downloaded today again it gave me the option to use a local account in the bottom left [1]
(note: the two pic's will look the same, but they were taken from the 2 diff iso's - granted it will try its hardest to get me to change my mind during the rest of the set up but the option is there.)
Third Test: I installed a fresh copy of Windows 7 Pro with obv a local account, I then upgraded 7 pro to 10 1903 pro using the media creation tool, I selected the option to keep my existing files and apps and allowed the upgrade to take. Told setup NO to all the extra's (location, personal ad's etc etc etc) and the install took using the existing local account and didn't prompt me to "upgrade" to an MS account.
As for real hardware I upgraded a friend of the families laptop 2 weeks ago from 7 to 10 using the media creation tool and it again upgraded without pestering for an MS account. (And I'll be upgrading another in the next week or two when they are ready for me to do it. They would rather have the process hand holded for them incase of any oddness during the process, so I'll be able to report back then)
I'll bash MS as much as the next person but I'm unable to replicate these findings. I know they try their hardest to push an MS account onto people (I run the insider build on my personal rig and every major update I get a prompt about all the wonderful things a MS account brings... But I am still able to say Nope, local account thanks :-)
[0] https://cejack.tk/2019-09-29_10-07-10-552.png
[1] https://cejack.tk/2019-09-29_10-21-05-939.png
EDIT: Fresh install with home and they moved the offline button. Typed in some random numbers in the account bar [2] and it gave me the option to use an offline account on the next page [3] which then took me though the process of creating a local account [4] - Is it an annoying dark pattern? Yes. Did they remove local accounts? Nope.
[2] https://cejack.tk/2019-09-29_17-32-57-607.png
[3] https://cejack.tk/2019-09-29_17-33-17-029.png
[4] https://cejack.tk/2019-09-29_17-36-37-343.png