been there too, not fun. i have a feeling that sometimes after not returning a call (or wtvr) for a while, it may get a bit awkward when they finally get an interest to call you back so they push it off and that can snowball worse and worse.
My stance on friendship is, technology plays no role in “why didnt you ever call me or send a text or email etc” (this is all only if the other person hasnt reached out first). I have many close friends that after not speaking to them for months (yrs?) and then meeting them by a wedding we can shmooze for hours. Theres no bad blood btw us cause we dont expect a phone call or text all the time.
Sometimes social networking can raise expectations of socialising (socialism?) and can damage social connections.