Remove out of stock on buying items some purposes are at follows:
1. in early game and u have to tp on jungle and u miss to buy the item because ur team bought the same item so out of stock
2. when u need to buy item on time by using autobuy hotkey button for example basher recipe "S" (For me cuz most of the time i use the autobuy command to bought quick instead of using cursor) and suddenly ur other teammate buy the same item sometimes i didnt notice because i was farming or at clash always im doing this thing so when u delivered the courier at the same time shared on other ally you wont expect that item on courier is not yours which is u wanted to buy and u notice it was not ur item its because of this Out of Stock.
3. Its only a suggestion if u play dota 2 its the same thing when u open the shop the items is not rolling which is really good
4. Another thing is this will improve the dota 1 for sure 
5. i know some ppl has the same idea with me so i know they will agree about this post
