Didn't Einstein say something like the reason he worked out General Relativity first was that he stayed with the problem longer rather than that we was actually

Didn't Einstein say something like the reason he worked out General Relativity first was that he stayed with the problem longer rather than that we was actually smarter than all the others in the field? And there is Edison's aphorism, something like "Invention is 1% inspiration, 99% perspiration." There is plenty to do for those who are not the absolute smartest.