You'd think that, but to an Eredivisie team it's just not worth it. The last few years PSV, AZ and Twente wasted energy in the EL while Ajax got knocked out early. Ajax proceeded to win the league partly thanks to this and they made a ton of cash. The runners-up get nothing (EL) because the CL playoff is stacked against our mid-level teams.
The other teams got max one round further than Ajax. That's only small percentage of us winning the league three times in a row