Re: retail
Oh no, I'm talking mainstream retail, you started trying to quote profits but I'll give them to you now, the hidden functionality behind many of the major industries you deal with, to show you how much I've been involved
First, 100% markup is called a "keystone", or "key" for short. I'll use that here as that's the way retailers talk to one another and between seller and retailer. All percentages shown are MSRP.
Consumer electronics ("brown goods"): 35%
Appliances ("white goods"): 35%
Furniture ("case goods"): triple keystone
Jewelry: triple keystone
Fine clothing: triple keystone
Recorded media: 30% (when purchased through OneStops)
Travel: 0
Yes I've been in all those industries and a few more (or their 'subdivisions').
Yes, brown and white goods only get 35% at MSRP but they make it up in other ways:
"Spiffs", commissions / bonuses paid by the manufacturer directly to the salesperson for each sale or attaining a sales quota
"Ad co-op", reimbursements for advertising when using approved ad copy, company logos or media
Rebates may be available to the retailer at the end of the year for reaching a sales quota. Small retailers can also get this discount by grouping together regionally into a "buying co-op", where they group their buying power into volume and then run a group warehouse to handle distribution to their members.
All these rebates and discounts aren't a lot individually, maybe 5% on average, but when you're only allowed 35% to MSRP and you may have to discount from there to get the bushiness, every little bit helps. This is where some trickiness can come in, when you try to comparison shop a product yet somehow the model number is different: the co-op gets the manufacturer to make a slight change, even if just the number, to resist comparison shoppers
Travel is "0", no profit - sold at retail. Instead, the agent gets a commission on the sale: 15-20% is usual. If a customer buys "direct" then the airline / hotel / cruise line etc just gets to keep that money instead.
Manufacturers can pay for retail display space (we did once) but at NO time do they / did we take a slice of the retailer's profits from the sale - not ever. That's double-dipping and I'm sure would hit against the Sherman act of horizontal integration here in the U.S.
I could go on about retail, as my family was in it for 1/2 a century and now I'm on the manufacturing side in a different (retail) industry, but you get the idea...