I'm not saying a good head server should not be seen. But, if a head server is doing a good job, it's quite possible for his time to be taken up with assisting elsewhere than your table (especially if your table has no special requests). Remember, unlike your serving team, which only handles 3 tables, he's got at least 1/3 to 1/2 of the dining room he's overseeing. Yes, it's nice if they "stop by for a quick hello", but it's not always possible.
And there are many tables these days requiring special handling, it seems.