What happens to all the domains that have unreachable email addresses or where people don't bother to sign up for this?
you lose them. I did a post 4-5 years ago were I was trying to buy a domain misspell from a squatter with bogus info. I tried for several years to contact this dude emails bounced so I took the steps and had the domain taken from him and bought it when it was available. I was accused of stealing in here by some but I could care less what they thought if you’re going to squat with bad info you should lose the domains period.