It's not lack of commitment or funnel strategy or anything else.
The biggest reason is because those who fail buy a traffic source that is so easy to mess around with and every guru teaches this strategy.
And you know what?
Most of these gurus who recommend you buy from their link is because they earn a commission and they don't even buy it themselves.
Traffic source is called:
If you are just starting out, avoid buying a solo ad at all cost.
Learn to generate leads yourself with Facebook ads, LinkedIn ads, Twitter ads, YouTube ads, Tik Tok ads, ifluencers, etc.
And also, every place you market you need to track so you know what platforms work for you and which ones don't.