Perhaps this will help:
On their whitepaper, they say "We accept fiat currencies such as EUR, USD, CNY as well as Bitcoins, and all our games are with licensed providers." You're only calculating their profits with the amount of Euros and Bitcoins they accepted. You need to include the other currencies they accept. If you do, the profit margin will be much lower.
This is the whitepaper:
https://ico.betstreak.io/wp-content/uploads/2017/09/betstreakwhitepaper.pdfThe quote is from page 3.
Edit: I realize that they only tell how much Euros and Bitcoin they accepted in the whitepaper. I don't know why; perhaps it was because they accepted a lot of fiat currencies, and it would be tiring to list how much they accepted of them all. But without those numbers, your calculations are way off.
I took all details from Betstreak white paper and ANN, It's clearly written they had wagered 3.5M euro and 1500 BTC in crypto in last 1 year. Just calculate yourself and you will be stunned with all details.