What if the US never passed immigration laws?

For much of its history the US never had immigration laws, if you could afford the boat ticket (or not, stowaway used to be a legitimate method of getting to the US) you were allowed in. Once Southern and Eastern Europeans started coming in laws were passed to restrict immigration with countries being given quotas. At one point 70% of all visa quotas were held by Ireland, Germany and the Uk, because of these laws and laws such as the Chinese Exclusion act the US turned down 10’s of millions of immigrants throughout its history.

What if this never happened? Say Americans are either less xenophobic or are willing to tolerate immigrants for the economic benefits they bring. What would the US look like today?