I've had a non-vanity phone number with five consecutive (non-repeating) digits for over 25 years. Even before the advent of phone spam and robocalling, it was receiving a lot more calls than my other phones. Many of the calls were from kids playing with a phone. It seems to be more likely than not that people press consecutive digits when dialing a "random" phone number.

Separately, I once bought a cell phone in a city with a brand new overlay area code, and they gave me this number: 424-210-0000. They were really surprised when I told them that I did not want it and had them port my old cell phone number to it instead. I suppose I could have kept it and then sold it to someone else. Apparently such things have value to some people, mostly businesses.