Ehhhh, you’re kinda’ discounting how broad “average” is. Some people cannot even get close to touching their toes without daily stretching (like me) whereas some people can grab their feet and they do nothing extra.
For people like me, daily stretching quite literally directly prevents injury both from exercise and when normal movement goes awry like when tripping.
I also don’t want to discount yoga! It’s good motion and position trianing and definitely stretches plenty, at least for ‘tight’ people like me.
I just wanted to point out that one doesn’t need to do an entire routine just for stretching. (although still, yoga’s a great way to start a journey with exercise, especially if someone isn’t a self-starter type)