Hyundai currently has about 800 dealers in the US. In order to offer a new brand with a separate dealer network they would have to get at least 150 dealers who were willing to invest at least $5 million (land, building, inventory, working capital, etc) to start a dealership. Hyundai is not going to create a separate brand until they know there are 150 dealers ready to sign on. Lexus has 230 dealers in the US, Acura has 270, and
Infiniti has about 200 dealers.
When you say "If I had the means ABSOLUTELY" do you mean if you were filthy rich and had money to burn? But if you had a total net worth of $5 million, would you be willing to invest it all and risk being bankrupt if it didn't work out? Running a car dealership is a business, and people don't invest in that unless they are pretty sure they can make a profit.