As you consider marketing yourself for your next gig, consider the difference between process and content.
Content is domain knowledge. People you know or skills you've developed. Playing the piano or writing copy about furniture sales. A rolodex of movers in a given industry, or your ability to compute stress ratios in your head.
Domain knowledge is important, but it's (often) easily learnable.
Process, on the other hand, refers to the emotional intelligence skills you have about managing projects, visualizing success, persuading other people of your point of view, dealing with multiple priorities, etc. This stuff is insanely valuable and hard to learn. Unfortunately, it's usually overlooked by headhunters and HR folks, partly because it's hard to accredit or check off in a database.
Venture capitalists like hiring second or third time entrepreneurs because they understand process, not because they can do a spreadsheet.
As the world changes ever faster, as industries shrink and others grow, process ability is priceless. Figure out which sort of process you're world-class at and get even better at it. Then, learn the domain… that's what the internet is for.
One of the reasons that super-talented people become entrepreneurs is that they can put their process expertise to work in a world that often undervalues it.