As seen, the fees stemming from fee-free ATM withdrawal not just a problem for Revolut, but for the entire retail banking industry.
Some subisidise it, as previously mentioned, by recouping the cost elsewhere via more expensive financial products with higher interest rates or more uncompetitive FX rates. Others use VC money/revenue to subsidise this. For the latter, the arrangements can last only so long before the the majority of capital is dedicated towards servicing fees incurred via ATM withdrawals.