Welfare in the Netherlands is ~1200/month. If you live cheaply (e.g. in a 500/month room in a shared house) that leaves more than enough for a transatlantic plane ticket every now and then.
I cannot find the number you report on that website. Please elaborate on where you got it from. I'm 100% sure you are leaving out important additional details, like that one has to have been recently employed.
You can get WW (werkeloosheidswet - unemployment law) for 24 months, like you say you need a sufficient history of employment. This is based on 70% of the minimum (full-time) wage, i.e. 70% of 1615.80 = 1131 euros/month.
Minimum wage is on the top of the linked pdf (download link here [1]).
Sorry if I was unclear, just looking for some ballpark numbers for the sake of the argument.
Source (in Dutch): https://www.rijksoverheid.nl/actueel/nieuws/2018/12/19/uitke...