They haven't been in Command of anything - but they have been sitting next to, and watching, someone in Command for quite a while before they get the opportunity.
Don't get me wrong - I came up through GA, piston & turbine, before airlines - and I wouldn't have it any other way. I think these guys miss out on an awful lot in aviation and there is a concern about the lack of breadth of knowledge, especially when everyone (training department, management) have come through the same system.
But I don't think that makes these guys any less talented or intelligent, and the difference that I can see on the line is almost negligible.