It's quite simple really - in a laissez faire system there would be no (or very little) regulation, no business taxes and no minimum wage - so 'big business' would have no reason to try and influence government policy.
This is how it (currently) works: Government imposes regulation and tax -> Businesses dislike this so lobby the government to lower regulation and tax -> Political parties need money to survive, so they do what big business want.
In a laissez faire system, the government doesn't impose regulation and tax, so there's no reason for businesses to lobby the government, so the whole sordid affair doesn't even start.
But again, we do not have a laissez faire economic system - that's not an opinion, it's a fact.
It isn't quite simple though is it? Unless you see it as a plain interpretation of definition. To usher in a revolution in society the easiest way is to do it quietly. The minimum wage isn't that is it? It has been used to drive down wages not to benefit workers, it has been circumvented by the use of zero hours, it's a complex gathering of business driven wants to serve business, painted as benefitting the ordinary person.
It is all stealth government by corporations. If it was an accepted and perceived reality by the masses there would be greater resistance.
You've pointed out a government wouldn't impose a business tax, how about impose one but avoid collecting it? Under Reagan GM tax bill went in the negative and they ended up receiving state rebates. In the UK we use tax avoidance as a means of maintaining the power structure, the bill for its maintenance being paid by the poorer members of society.
As I said earlier it's a Cartel. Choosing to label it as being neither one thing but another misses the point, it's just semantics, but the whole system is skewed so regardless who you vote for you end up with the same outcome, Einstein's accredited definition of lunacy.
Laissez faire, corporatism, whichever, whatever, but the existing system fits in with Mussolini's own definition of fascism. everyone has a place to serve, can't do it? don't like it? Tough there is no safety net, sick, poor, old, doesn't matter, you're expendable in the pursuit of profit. Abhorrent.