They should just secede from the union and be a small city state.

Would it benefit anyone? No. Would it be very costly to make the transition and potentially wreak havoc on the community? Absolutely. But would it create a sense of civic pride and feel good for the residents of Point Roberts? Also no.

What territory swaps a few years ago?

It's also too late now, even if you come to a political agreement you'd have to buy them out, have to hear about unseating American families, and I doubt Canada is willing to do that. What's the point for that insignificant land?