This argument doesn't really work and it never has and unfortunately it was Tim Epic himself who solidified that it doesn't work because he has already admitted before that by not charging 30% they quite literally can't do certain things:
View: https://twitter.com/TimSweeneyEpic/status/1474955912473415683
Because 30% isn't too much, it's actively used by every other storefront to do consumer friendly things like:
* offer the aforementioned gift cards (gift card regulations means Epic would actively lose money if they offered gift cards for anything other than V-Bucks)
* cover high merchant surcharge fees (in some countries some of the merchant surcharge fees are so high that Epic would lose money from their low cut, so they pass the fee onto the consumer instead of covering it, which is completely different from how basically every other retailer on the planet works because they all take "high" cuts, even outside of gaming)
And of course, actually work on their storefront faster than the speed of snail because the low cut is making it harder for the company to stay afloat.
Tim Epic saw a system that basically every physical retailer and every other digital retailer does, went "lol that's dumb", and has been reaping the consequences since.
If your cut is so low you can't actively provide gift cards or cover consumer's merchant surcharge fees globally, it's too low and you shouldn't be forfeiting consumer friendly stuff like that especially when the lower cut did not at all "pass the savings onto the consumer".