If the competition is already charging $10 but could get by just fine if they charged $5, then that means they have far more capital available than you do and can afford to wait for
you to go out of business.
It also means they have additional capital to
a) Advertise more
b) Improve ingredients and taste
c) Do all sorts of things to improve the customer experience.
In short, there are benefits to charging more from the outset that aren't always obvious until you're playing catchup.