Most older people didn't get exposed to computers until they were already grown up and out of school so they never got any kind of training on them or even had a job that required the use of a PC. As a kid you don't need formal training because you're ignorant enough to just try the wrong things assuming there are no consequences. Adults always worry about consequences which prevents the trial and error phase of learning how to use a computer. You can see this in how older people use computers they're always trying to be very deliberate and trying to remember what all the steps to doing something are before they start. This is why older people really need education where younger people just "pick it up".

That said I know plenty of 60-something-year-olds that would make you feel like you're the one who should be getting made fun of. Granted they're usually people who have been in the industry for decades but they do exist.

If we're generalizing here as a 30-something I honestly see a huge drop-off in computing skills in the new generation coming up that's just had the Internet since birth. They don't know how anything actually works and everything for them has been made so easy a child could use it. I have university students coming in who don't even know stuff like how to copy-and-paste files and folders let alone select multiple at a time. Growing up with a smart phone and social media doesn't make you a technology expert. Also "I use Linux" doesn't mean anything anymore when your grandmother can install Ubuntu. Don't get me started on CS students who can't even fumble around BASH.