It's really not all or nothing, despite the way you're trying to spin it here.
That doesn't touch the economics of the thing, though. We are talking about a $100K or so price tag for the major presence at the con that folks are saying they expect.
How does that pay off well for them?
Let us break it down for a moment - on Amazon right now, the PHB is selling for about $27. Amazon's standard markup is 15%, so let us use that as a gauge - WotC gets $23 per sale. Let us ignore the production costs on that book, and say it is pure profit. They'd have to sell 4300+ of them to break even on the Convention. Is WotC's presence at the con going to lead to them selling 4300+ more PHBs then if they weren't there? Or 4,300+ more of *any* products?
If we can't make an argument that this is economically positive for WotC, we shouldn't be expecting them to be present. If the argument is really, "I feel disrespected for WotC not taking the effort to be at *my* con," then the issue isn't WotC's marketing, but our sense of entitlement.