Fair enough. There is a certain romance to crossing the atlantic by ship, though. That's been on my bucket list for a while - IIRC a ticket is on the order of $1-2k for a weeklong journey from UK to US.
The exception is the Queen Mary II, which is an ocean liner that still does regular trans-Atlantics.
Of course both Europe and North America are large continents with a lot more to see than you can do in a week, but few of us have the budget to be a world traveler for a few decades to see everything.
Right, the point is it might be six months, since a lot of cruise lines will do only one crossing for northern/southern hemisphere summer toggling.
e.g. here in Seattle the cruise ships that go between here and Alaska make a single trip down to Australia or somewhere in the fall, and then don't come back for half a year.
So yes, like you said - probably fly back.
I think you can get a ticket for less than $1k,though you'd probably be cramped with no window.