Massive newbie syndrome.

50% of the population is married.
20-30% are in committed relationships.
This leaves roughly 20-30% single.

No matter what anyone tells you it is not possible to approach and get any kind of result from the vast majority of these other than a number, under the radar. This is where you've bought into the pua lie falsely. Even someone heavily selecting is going to bump into many, many taken people, resulting in failures. It is easier in clubs/pubs, few are married. Without a boyfriend clearly in sight there are few tells for being taken before an approach though. This is why the success rates you want are not possible.

You've been taken in by all the marketing, hype and sales lines.