I feel like the main reason pay-to-play for European leagues would not work is because most people will not see any of this money come back their way and it will primarily be to fund prizepools for the top divisions and compensate community contributors. The amount of money would also have to depend on the country, due to income varying heavily across Europe. Would be a logistical nightmare. Either that or it would have to be such a low amount that it might as well not be worth the effort.
Also no shot anyone is (voluntarily) programming a payment system into the Wordpress mess that is ETF2L.
People who want to financially support ETF2L can easily do so by donating, there's been some fairly generous donations in the past.
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