Yokohama tyres are usually considered soft, and accordingly, its tread wears out quite quickly.
I would strongly disagree. 185/65/R15 is a common tyre size, and almost all brands offer it.
The shopkeeper does not see right, and is trying to sell which he owns.
(Its a Dilemma here k jiss k paas jo hota hai, wo ussi k baray mein baat karta hai, and Taareefain karta hai, and baqion ko zero kar daita hai)