I ran the contracting circuit during my corporate years, so that’s just part of the terrain.
In what was then my specialty there were rarely opportunities to have one project conveniently start as soon as the previous one finished, so I had between-projects periods on a regular basis.
It was far far easier to get a new contract when I wasn’t busy with existing commitments. I had time to do what I needed to do to prepare, assess options, sort/consider/research jobs and employers, revise resumes, write covers where appropriate, interview, and negotiate. If one is specialized in a particular piece of software, as I was, then taking the time to research which companies use that software and what the needs of those companies are is both invaluable and unreasonably difficult to do correctly in the midst of another commitment.
Working projects where your commitment is really 10+ hours a day doesn’t leave time to do the whole job search thing with the level of commitment necessary to swing a good deal.