Most people date quite a few people before they find the right person, no reason to think that online dating is going to work any different.
Sure some are lucky to find the right person sooner rather than later, but typically that is not the case.
I dated and had at least 3 serious ( more than a year) relationships before I found my wife when I was 28.
The older you get though, the harder it will be to find the right person.
Not only is the "dating pool" less but as we get older the things that we don't care that much about when we were younger (just looking to get laid and have some fun) start to carry more weight in our decision making.
Of course some of us are just assholes and don't deserve to have anyone decent in our lives and shoudl just stick to meaningless sex.