Well, this is a side effect of the EUR area and SEPA. Not Revolut charges you for transfers, the other banks do. And customers with EUR accounts in the SEPA area profit from a very competitive environment where there is no difference between national and international transfers anymore.
Revolt is a completely different business model. PayPal makes a profit by charging merchants a relatively huge fee for their services. They also make money by applying bad conversion rates for international payments for their personal users. They set up a worldwide structure of accounts to pay out their customers and to reduce their own costs.
Setting up a similar infrastructure would be very costly for Revolut. It might be hard to offer a basically free product with good exchange rates and offer all sorts of other costly services like national accounts for free in addition.
I am not saying that they don’t get there. I am not saying they shouldn’t get there. They might eventually when they become more international. But right now, part of why they can offer great value for customers in SEPA/EUR nations are the very special circumstances.