Why should exchanges be happy? They have less more income as long as they don't increase the withdrawl fees.
1st, there are less chances users will move coins off exchange to their own wallets, unless its huge amounts
so fees are actually negligible compared to overall amount of tokens. Most exchanges like it when you keep coins on
their wallet instead your own
2nd, many actually increased their own fees, hiding it behind "network congestion". Case in point, ETH withdrawal fee
is currently around 16USD (0.0093ETH) on one exchange, while USDT fee is 33 USDT on same exchange (and same
exchange could use USDT on OMG to lower fee...which it maybe do, and keep that money for themselves)