Bitcoin $800 when shops/stores take Bitcoin

[First77]

I read, that shops/stores sell Bitcoin and convert them into cash after the payment is done in Bitcoins.

[franky1]

shops/stores use things like bitpay to accept bitcoin

bitpay then do PRIVATE O.T.C swaps for fiat away from exchanges, and then shops recieve fiat.

in short places like bitpay dont affect the public exchanges, and thus you wont see massive sell off of coins on public exchanges due to shops/stores activities