Hard to say in hindsight. I’ve been getting contacted by recruiters mentioning my SO profile for more than a decade, but I’ve also been active on Stack Overflow since the very beginning, and earned a lot of reputation very early on (and much less since). I’ve since dropped of the first page of top users (second or third now) but I can’t tell whether that’s led to a decrease in contacts (it probably has but that’s been balanced by an increase due to seniority in my field).