Anyway, it does work, people just aren't told to do it firmly. Doctors dance around it.
I have been using pullout method for 25 years, very consistently with basically 50 women at this point, and not one pregnancy scare (other than one girl trying to pass off her pregnancy as mine once). Same for many of my friends.
does nothing about stds though.
https://www.plannedparenthood.org/learn/birth-control/withdr...
For every 100 people who use pull out method perfectly, within a year, 4 will get pregnant. Since not everyone does a great job doing it, in reality 22 get pregnant every year.
Here's a great overview page: https://www.plannedparenthood.org/learn/birth-control in summary, condoms are 87% effective at preventing pregnancy, and withdrawal is 78% effective.
For a going-steady couple that isn't worried about STDs, keeps an emergency contraceptive ('morning after pill') ready for oopsie mistakes, and live in a country that grants women bodily autonomy (or have discussed and accepted that a mistake might lead to a child), pullout is a perfectly valid contraceptive mechanism. There are better, but considering that basically every method except a condom/internal condom can cause extreme discomfort or bad side effects to the woman in the relationship, I think it's totally fine to choose pull-out.
And they had 86% adherence for a year. If they'd studied this farther out and it went the same way as basically any study that's done that, adherence would be a lot worse in another couple years. And that's in a group that's exceptionally motivated vs. the general population—has an actual illness they're trying to treat, and has opted in to the study knowing what it's asking of them and for how long.
[EDIT] It's not that your approach can't work, it's that if (for example) people had as hard a time following the directions for condoms as they do following diet & workout plans, we'd never allow condoms to be sold as contraceptives, they'd not even be close to being OK to promote as useful for that purpose. It wouldn't matter if a few people could follow the directions and it worked 100% of the time for them.