I an confirm the pricing via
Godaddy India they are charging $16 usd/month for a cPanel licence (change the currency to USD at the bottom left). Given the price for cPanel "Premier" currently is $53.99 "retail" it does look impossible.
As GoDaddy is a
cPanel partner they do get a discount on the pricing and access to the "Auto-scaling" function (all this information was found via a DuckDuckGo search for "cpanel partner pricing" so I don't believe it's confidential). Auto-scaling means they'll only pay for what is being used - so when someone sets up their GoDaddy cPanel hosting account, GoDaddy will only be charged for the "Solo Cloud" account (partner pricing $7/pm), when they get up to 5 accounts, it'll be the "Admin Cloud" price ($13.50) - so GoDaddy won't be paying for what they aren't using.
As GoDaddy is a big big company, I'm also guessing they would spend over $5million/month on cPanel licences and they probably have quite a 12+ cPanel certified staff - both of which will combine to give them a discount of 38% according to the licensing guide. So that'll bring the price of an "Pro Cloud" (30 users) down from a cost price of $19 to $11.78 and a "Plus Cloud" (50 users) from $34.50 to $21.39.
I'll therefore guess that GoDaddy has run the figures and worked out the majority of their cPanel customers use 5 accounts or less (cost price $10 - after discount $6.20) which would leave them $9.80 per server per month (and we'll be talking about thousands of servers here) to pay for the more heavy users. Of course, if everybody started putting hundreds of accounts on each server (so GoDaddy have to pay "per account" at over 100) the costs would go through the roof, but I'm sure they've worked out the break-even point and know roughly have many user accounts each of their servers is likely to support (you aren't going to be able to realistically get 100+ on a 2 CPU/4GB RAM machine) and they've taken the cost of the "hardware/VPS" into account - along with costs of providing customer support etc etc.
It's all finance and business planning, combined with big discounts for lots of custom.