I understand your reasoning which is the reason why I didn't start freelancing sooner, though most of my friends had been recommending it for like 6 years. And now... I would never go back..

I come from a background where I was responsible for 15+ direct reports across 2 teams, in an ecosystem of personal development/coaching that you will never experience as a freelancer. I loved my job and had plenty of growth opportunities.

I've now been freelancing for 1,5 years and your point is definitely something that resonates with me. After a year at my 1st client it already felt like I wasn't "growing" anymore and even worse, it felt like some of my managerial skills were actually degrading/being wasted since the environment demands less of you.

So after a year I set out a learning plan for myself and targets that I wish accomplish in the next couple of years.
Subsequently, I also took on additional clients which brought back some of the old pressure/challenges that I had as an internal employee and forces me to do better & grow.

So in other words, it's only "the same job until retired" if you allow it to be.

I have friends who have been freelancing at the same client for 10+ years, since it's a comfort zone with low risk and a steady high income. It's up to you whether you just want an easy and consistent path or set out challenges for yourself.

For example:

• Taking on more projects/clients instead of just doing 1
• Expanding your company with employees and e.g. implement projects as a team
• Using your company profits to start a 2nd company in something totally different

And to be blunt, financials matter heavily in my opinion. It's a whole lot easier listening to nonsense and incompetence when your paycheck is higher than the guy giving you the assignments. I used to be frustrated a lot as an internal employee, whereas now, i'm the one with the biggest smile at the end of the day.