why do Ты think princess персик is the main princess?

Because she is pretty and girly and better than daisy

because Nintendo made her before маргаритка или rosalina and plus she the princess of the гриб kingdom :)

because she has mario who rescues her about each day.

Because Shigeru Miyamoto created Princess персик to be a part of the main cast.

маргаритка doesn't get the same luxury because Super Mario Land was made without Miyamoto's knowledge. (Or so I was told.)