Because self-employment removed the structure that used to start your work for you. As an employee, you had a boss who asked, a colleague who waited and a meeting where a missing task came up. Now you hold all three jobs yourself, and you never got a handover.
Take the new offer page you've been planning. Nobody asked for it. If it slips by six weeks, nobody calls, and your calendar still looks full. You work all day, and the page that would move your business sits untouched.
That isn't a lack of drive. Your effort is real. I'd call it a mismatch: your hours go to whoever is waiting, and nobody is waiting for that page.
Read the full article: https://impruvement.com/blog/procrastination-as-a-self-employed-person-why-does-it-hit