It is turnover season in tech, and I’m trying to figure out why.

The Instagram founders called it quits last week. They’re seriously rich and young enough to do something else. Or many somethings else.

Also last week Oracle disclosed without explanation the departure of Thomas Kurian, the company’s president for products and the man considered Larry Ellison’s technical deputy. (Kurian figured prominently in my contentious 2015 profile of Oracle co-CEO Mark Hurd; I quoted an anonymous Oracle leader calling Kurian “a giant pulsing brain that is most like Larry.”) Kurian worked at Oracle (ORCL) for decades and also has time for another career.

Then there’s Sridar Ramaswamy, Google’s (GOOGL) top executive for its ads business, which is most of its business. Google said Monday he’ll join Greylock, a venture capital firm, as a venture partner. That’s a term of art in an industry where terms of art matter that means he’ll make investments but isn’t yet a full-on member of the team. (The inimitable Fred Wilson, a founding and full-on partner at Union Square Ventures, explains the nuances of venture partnerdom here.)

Is there a rhyme or reason for all these middle aged men, all long tenured in their jobs, leaving now? Investment bankers tend to leave in February or so, minutes after their annual bonuses show up in their checking accounts. But tech execs follow less of a scripted calendar.

Maybe they spent their summers either enjoying themselves, or, for the umpteenth time, watched their families enjoying themselves, and decided enough was enough.

One thing is nearly certain: There will be no neighborhood bake sales to make sure these gentlemen are well provided for in their dotage.