At what stage do the studios/distributors make profit from physical media?

[Bk_Tan]

Hopefully this is the right forum to ask this. Had asked in another thread but was buried.

Does anyone have any insight on what and when the studio/distributor makes on the Blu Rays they issue?

Do they sell the stock to all these e-tailers/retailers at a set price and therefore take the money upfront or do they only receive the money when the product is actually sold, and therefore they only get the return at whatever price it was sold at?

Since no one really uses the RRP, if it's the latter, then the studio gets a varying amount dependent on what the e-tailer prices it at? That doesn't make much sense.

But at the same time, if the Blu Ray is selling at $5 off a $25 RRP, what price did they actually buy it at from the studio?

Do retailers request these titles from the studios to stock their shelves/warehouses or do the studios function like Amazon marketplace sellers except product comes from the Amazon warehouse?

Just wondering how a studio will determine whether a title is profitable/worth reissuing etc. and that would come down to how the whole process actually works.

Thanks for any answers