In programming -- and, I think, perhaps in most industries -- more people fall behind in learning because of their job than because they're out of the daily grind. Any large-scale enterprise is chock-full of devs who have plenty of experience developing inside Websphere, Liferay, Sitecore and so on, but who haven't had the time between work, family and sleep to gain knowledge and experience in SPA development, CI, CD, microservices, and so on, let alone more outre topics like ML or NLP. Giving knowledge workers the opportunity to sabbatical out and build new expertise would benefit both them and their employers.