I think perhaps we'll just have to agree to disagree on this.

I need to reiterate that your former colleague is just living within the system we have, and I can't make personal comment on whether or not he's done any of the worse things I mentioned.

Initially, it was him and his wife, yes. Though they now have a decent sized company with a few hundred employees.

How is this not proving my point?

He has a decent sized company, that generates profits for him from the labour of their workers, who share in a smaller share of those profits. And this is the typical arrangement. I think it's pretty hard to argue that (in most cases) the amount of profit people generate vs what they get paid is just.

I'm sure he's worked hard - well, I guess he has - but it can't be denied that his excess wealth is only possible because of other people's continued labour.

if he should keep all the work and wealth to himself

This is fundamentally what we disagree on. He didn't "share" the work. He had an idea, worked hard on that idea, and then hired other people in order to grow his company and make more money. That's capitalism, and people pretend as if it's the only way we can structure society. As if innovation would stop existing without the profit motive.

Innovation would happen regardless. The profit motive only "drives innovation" because that's how we've structured things to work. I also find the claim doesn't hold water because a huge portion of innovations are already from publically funded university research which otherwise wouldn't be funded.

Currently a few people profit massively off other people's labour, and looking at wealth inequality, and pay inequality, it's getting worse and worse every year.

Unless one has the opinion than a tiny percentage of the population is thousands of tens-of-thousands times more productive and deserving than everyone else, then it's kind of hard to argue the current state of the world makes sense.

I have no issue with some people making more money than others to reflect their harder work. But only to a point. The profit motive seems like a stupid way to do this though, because it's also pretty plain to see that innovating is probably not even the main way more profit is achieved.

Monopolies, dark patterns, price gouging, wage theft off-shoring and other anti-competitive behaviours are far more common paths.

Again, nothing against your former colleague personally, as I don't know him.