I'm not sure how far this premise stands. There are plenty of historians working in the Netherlands and elsewhere on some aspect of Dutch history, irrespective of whether there are dedicated PhD or BA programmes that specify it as a particular subject. Why should there be such programmes, when the content could be readily covered in any number of other subject areas (European history, Atlantic history, global history, to name a handful)? Why should the relative 'importance' of Dutch history as a subject be measured by its uptake in the United States, in any case?

More broadly, the holes in academia, as you put it, are to some extent self-correcting. All scholars have direct incentive to find a neglected area of the human past, and make the case for its significance. That's academic research in a nutshell really. If Dutch historians (or historians of the Netherlands) are able to make the case that there are elements of Dutch history that are poorly understood and are important, then that can then inspire and justify subsequent interest and resources, though per the logic above, I don't really see Dutch history emerging as it's own distinct genre anytime soon because there's no real need (and compared to many other fields, I'd say that the Dutch have hardly been neglected as historical actors). But we can see this process as having happened in recent years in any number of fields, as new methodologies and focuses have led to realignments in the historical profession - the transnational and global turns, for instance, have had a huge impact on the hiring practices of many universities, while even newer fields such as the history of emotions are staking out their own claims (and winning resources in the form of dedicated research networks and centres of excellence). While the pace of such change could obviously be quicker, many historians often grumble at how 'trendy' subjects get all the funding and attention despite being less rigourous or well grounded, so it's always going to be a balancing act.

If the question is more about history education - that is, why don't we learn more about the Dutch in school? - then that is an impossible question to actually answer, as educational standards and focus vary so wildly, even within countries. Different perspectives will also be inherently (and justifiably) parochial - the goal is unlikely to give students a balanced, overarching view of world history, but rather help them understand their own heritage and society. The goal is certainly not to create an objective, neutral hierarchy of 'important' societies and events - not only is this a bit pointless, it also flies in the face of what historians are generally trying to achieve with their analysis, not to mention leading to all sorts of problematic questions about who gets to make this kind of value judgement and on what basis.