I'm 35, so while I have a bit of time before a typical age midpoint, I see it approaching. I don't see a midlife crisis approaching, though. I long for a sports car, from a Miata to an Aston Martin, but that was true when I was twenty and will probably be just as true when I'm seventy. I'm stronger and fitter at 35 than I was at 25. I have more goals now than I did at any younger age, and not only do I see how to achieve them but that path seems achievable. Midlife is just an age and doesn't change who I am. My theory is midlife crises are sometimes used as a defense, sort of "I need this red sports car because I'm 45, so kids you won't get to go to Disney World or summer camp this year." Really it's just someone justifying their (unreasonable) actions.
When I see how some people live their lives I can understand why a midlife crisis is a thing but I really don't see it happening as often now. The type of people I'm talking about spend their twenties talking about all these things they want in life while not having a plan to achieve them and actually doing things to hinder achievement most of the time. The other common scenario is someone having a mental health issue that they just assume is who they are and try to live with until years of " living with it' coupled with one bad situation come to a head. I guess in general that would be summed up as people who don't really take control of their life.