Do you have any problems with certain exchanges? What are they or what it is? Are you sure all exchanges are a scam? Including the top exchanges? And are you sure nobody can't earn money from exchangers? Have you may poll to all members here?
Well, silly of you.

First,
never judge a bad exchange to be similar to others, never judge all exchangers are bad because there are many reputable exchanges as I use until now.

Second,
You must have criteria or points why you accuse all exchanges are a scam. If you do not have sure reasons, it means nothing. You said "all exchanges"

Third, the withdrawal will take in various time, depending on each exchange itself, the fees are also various.

Fourth, I see that you have been losing much money for trading in exchanges. But look, you need only to learn more and trade carefully. Many of us are still earning big profits by trading in exchangers, bot usual trade, or even future trading.
The profits to gain will depend on how we make it and how we analyze including set the strategy