Because the US, like most other countries, has decided for various reasons that unlimited immigration is not a goal of visa legislation.

You would be surprised to find many immigration visas that have no limits then.

So do you want unlimited immigration?

It's not unheard of. Instead of putting a hard limit and playing the random number generator game with peoples' lives, maybe approve visas on a case-by-case basis...?

To me that sounds like it would make the situation much worse than it already is. Instead of a lottery there would be a waiting list that is hundreds of thousands of entries long and backlogged for years. They'd have to sort by salary or something so that companies don't have to wait for years to hire highly qualified people

How many cases?

100, 10K, 100K, million?

7 billion if it they want to.

You'll need to add more meat if you want me to take a bite.

Why would I do that, I already know you are trolling

Yes.

Will an answer to that question completely change your mind?

Also, you imply that immigration restrictions decrease cost, but it's quite the other way around.

An answer to that question will allow me to offer a token suggestion that may make OP reconsider his stance ;)

immigration restrictions raise salary for people like me, citizens. Most countries have some form of immigration restriction for similar reasons.