There are plenty of locales where broadcasts cross state lines. I grew up in an area where we got Boston (Massachusetts) and Providence (Rhode Island) stations. NYC stations cover three states. I'm sure there are plenty of other examples (probably involving even more than three states).

So the justification for federal intervention (interstate commerce) is there.

Of course, that doesn't prevent the feds from letting the states handle it, but it does create an incentive for some states to want the feds to handle it.

New England and a few big metros that straddle the boarder are issues, but even there the states involved could manage it together.

I think the New England states could manage this together fine.

I agree, the constitution grants the authority to the federal government to. But more and more, I think we should just let the states deal with as much as possible. It seems pretty clear we are far from a national consensus on many basic issues, and the constant winner take all grab for power is making things worse.