At least one output is a change address so at most 73 customers
Initially, when I wrote OP, I forgot about change address but minutes later, I thought of it but still not sure there is or is not change address in that batch. The possibility of having change address is big but it is not 100% probability. It is reason I hesitate to edit OP. Anyway, thanks for the correction.
but it can not be accurate because exchanges withdrawal fee are not the same, they are different from exchanges to exchanges.
I left a note that for other exchanges or other periods, do your own research and calculations.
we as the users shouldn't assume 'withdrawal fees' equivalent to 'network fees'.
They are different things but somewhat can be connected IF exchanges apply dynamic withdrawal fee. In reality, most of exchanges are using Static (fix) withdrawal fee that does not correlate to transaction fee on the network.
Oversimplistic way of looking at things.
Those exchanges need to make money, what to you might look like a simple payment has people verifying, monitoring, and giving the go-ahead for it, it has support, it has an infrastructure to pay for all of it. Yeah, they make money from withdrawals fee, it's normal, I would be more amazed if somebody would do it for free.
There are many factors behind and as I wrote in OP, it is not an attack on exchanges. Instead, it is a reminder to people to beware of what they get from exchanges (chances to trade, etc.) and what they get loss from exchanges (withdrawal fees, ie.)
I know exchanges need to have teams behind to keep their services operating safely. They need to have salary budgets for their staffs, and so on. If people decide to use exchanges, they automatically accept those (dis)advantages.
Exchanges get their incomes from many sources: maker/ taker fees, listing fees, withdrawal fees, and partnerships with crypto projects, or manipulate their order books and make liquidations, etc.
Definitely, their fees could be cheaper, but fees are there for companies to make money and maybe for clients to keep as many coins on the exchange as possible so that their liquidity would be as high as possible.
Higher or lower, community can make voices but must accept ToS to use exchanges.
Look at it in % of
BTC is better as the figure in USD will be changed with bitcoin price. The percent is not small --
93.1% go to exchange, the rest (6.9% is for transaction fee to miners)