I really wonder if all y'all think getting your cash refund from a bankrupted company would be easier than dealing with a voucher.

cause maybe you don't get it, but they don't issue vouchers just so they can mess with their customers. They sort of issue vouchers so they can keep existing...
"oh, but the governments would just bail them out". Guess what. Government can just as well decide to let KLM fail, they've had a 100 year run. And in the summer there would be Rijksluchtvaartsmaatschapij with their iconing orange airplanes instead.
Your claims against KLM? Well sure, they are court accepted. You can expect your 1 euro per 1000 euro claim as soon as the airlines collection of huisjes is auctioned off.