FFS he has played ONE game !
But your assessment of Holla was harsh. He played most of his games for Groningen, and they are a proper club - averaging 19,000. Den Haag (his recent club) are a bit smaller, but still comparable to an average championship club in terms of size.
The Dutch league isn't anything like as lop sided as Scotland, to be fair. Sure, Feyenoord and Ajax are the only two teams capable of pulling in 45-50k, but PSV always manage over 30k (and have won numerous titles themselves, far more than Feyernoord), Twente get 29k (and won the title under McLaren) and there are another 4 or 5 teams averaging 17k+ who often go quite deep into the Europa league.