Bunkers are short term 2 weeks to 30 days, giving protection against blast (location dependent) and initial rad fallout. For protection against hoards of people it is temporary and only gives one a false since of security, I'll mention it again, the bunkers achilles heel is the ventilation system! I'm not against bunkers though that be only in certain locations where it would be advisable such as Tornado Alley, in/outside New York City, Chicago, Seattle, Bremerton/Norfolk naval base, DC etc... (if only concerned with nuclear war and/or tornados)
So much of the sales pitch today reminds of the sales pitch in the early 60s and for the most part like then it is based on false hope false security! youtube has an awful lot of snake oil talk and the same with certain television programs.