What is your proof that I will earn more as a freelancer?

As a freelancer, I have been approached a few times over my 20+ year career by people to work for free in exchange for future revenue share. I have declined this each time and on each occasion, when I followed up a few years (or even few months) down the line, the venture was dead.

So in my personal experience, there is basically zero chance of getting that future income. But I am sure there are some people that have success, so I will grant there is a chance, albeit small.

Yet you make claims about earning more and building my pension. I think this is misleading without actual proof that there is very high certainty that it will work out in the freelancer's favour.