It depends on the strategies of the mobile phone companies.
Now majority of the companies prefer dealing with the customers directly and selling via online sources, like official websites, Daraz.pk, etc.
Such practices save much additional costs, like need for brick and mortar stores, etc.
So do not take it as if big stores do not deal with Realme, then Realme might be a substandard brand. Its not like it.
I hope, it helps and guides. Thank you.