Well I mean you don't. And you know that. And 95% of internet users know that. It's just an issue with elderly folks not being familiar with this UI
Maybe the real solution is a simple explanation for how to use a date picker component. It'd help those users not just on this site but on many other sites in the future.
Tbh I don't really know what improvements could be made to the picker itself. It looks pretty consistent with the implementation of most other browsers and OSes and even most native components I've seen
I'd love to hear actual thoughts on improvements though