Because people get tired of that old people bullshyt especially when concerning these so called "bosses" and managers disrespect people, talk down to them, etc.
I almost left my company this week, I was trying to switch contracts companies but stay in the same position under a new company. Wasn't going to warn them or nothing, dude called me trying to "discipline" me about my timecard and I laughed at him through the phone and was cool with whatever he was trying to threaten me with, as long as I got paid, but this clown wasn't my boss so I was like "really

" like you can't fire me or do shyt to me but stop my direct deposits... I was like cool do that then

, I can cash paper checks on my phone my shyt just better be there
Then he tried to compliment me on my work but after that I was like
They send me emails and I barely respond. Only reason I responded recently was because these fools be fukking up with the paperwork they want me to fill out by a certain day but then all the shyt don't be there...
Basically, what I'm saying is people don't got time for that shyt no more. Ghosting them will not affect your career unless your next company actually calls them, which if it's not listed they won't. With the right degree, certs, time in field you can still get decent work some place.