Or in most cases, it's parental neglect with both parents working full-time jobs with barely enough time to take care of themselves?

From what do you infer "in most cases"? What are your statistics?

Parental availability has been steadily declining for decades - the same decades where video game usage took the place of other activities. You can do your own research. If it's difficult to get hard data, use soft data and draw inferences, but don't invalidate what data we clearly have and from which plenty of valid use can be extrapolated.

No one else gamed with their parents? No one else games with their kids? My anecdata disagree with the causal link you're suggesting, fwiw.

Books and video games were my way of being 'out of sight, out of mind' as a kid. Sadly, the less interaction I had with my parents, the more peaceful my life. I loved being left alone during the summer time.