Is there any way to make it so tables too wide to fit on one page break at columns automatically like is currently done with rows?

Unfortunately not at the moment, the CSS table model does not allow for such things. If you have a table that is just a bit too big you can scale it down with @page { prince-shrink-to-fit: auto }, but if you want a very wide table to be broken horizontally over several pages this isn't yet possible.