Those philosophers long ago in the seventeenth century laying down the ontological cast for the modern age were fighting especially against one variety or other of medieval scholasticism. This long battle ended with the victory of the modern scientific mind-set with its absolute, mathematizing, scientific method. Today it's a very different fight that is invisible to most, perhaps to all, but especially to the agents of the Geistesgestell, all of whom are players in the modern age's rigged mind-game in one of its bewildering, inexhaustible variants.
The problem is that the scholars do not think in concepts, nor do they work with them in their writings. Instead, they argue logically, citing and alluding to various philosophers and to other scholars. In this way they aim to make progress in whatever discourse is being cultivated. A concept, however, requires much more. Thinking conceptually does not amount merely to defining your terms precisely and arguing consistently in line with your definitions.
A concept here is theoretical, that is, theoretical in the original sense of Greek _theoria_, whose Latin translation is speculatio. Today's theory is not up to the mark of _theoria_, and speculation has become a pejorative term describing thoughts that have not been subject to testing by scientific method and are therefore unscientific. _Theoria_ is the investigation of beings qua beings, an ontological enterprise. Hence Hegel's philosophy, for instance, is speculative in this sense, and Hegel criticizes English and Scottish philosophy for lacking speculation. To the present day, English and Scottish philosophy, which in the meantime can be called analytic-positivist philosophy, lacks the ontological dimension of speculation.
All the greats in philosophy from Plato and Aristotle through to Kant, Hegel and Heidegger are speculative, ontological, conceptual thinkers. Their concepts grapple in a connected way with grasping the phenomena in their being, i.e. their mode of presencing, in which they show themselves hermeneutically AS such-and-such. The interconnections among the concepts have to be respected and mastered to understand what these thinkers are saying, always bearing in mind that it is a matter of speculative concepts, i.e. concepts born out of what Heidegger calls the ontological difference, which Aristotle captures in his formulation _to on haei on_ "beings insofar as they are beings", i.e. beings qua beings.
The ontological difference concerns the hermeneutic cast of an age that defines how beings as a whole present themselves AS the beings they are within the time-clearing. Any historical movement in the hermeneutic cast of an age demands on the part of thinkers a recasting of ontological concepts that has to be performed rigorously, carefully. Thinkers do not 'speculatively' make up a new hermeneutic cast, but are sensitively receptive to an alternative historical cast arriving.
Modern scholasticism is not up to this task. Even and especially when it is dealing with genuine ontological concepts from one great thinker or another, it only ever talks about them and does not work with them. The phenomena philosophy scholars refer to are spoken of only ontically, not ontologically. Therefore there can be no movement and advancement in such a way of scholarly thinking, but only an endless, inconclusive back-and-forth among various argumentative 'positions' each with its own adherents. The positions are invariably labelled as one -ism or another, and the scholars move skilfully among these -isms in formulating their own position. That is their sub-game within the modern age's mind-game.
Thus the Geistesgestell's mind-game proceeds complacently among the thicket of scholarly texts without so much as a speculative glance at the simplest phenomena themselves, which only bamboozles scholars, for they have never bothered to look and contemplate. Nor have their likewise complacent teachers taught them conceptual thinking. Complacency here signifies a lack of courage a.k.a. cowardice, for you will be mercilessly punished if you genuinely risk thinking slowly through the hegemonic hermeneutic cast of the present age, thus exposing it and putting it into question. Modern philosophical scholasticism is flying blind, lacking the ontological orientation that would open an alternative hermeneutic cast of mind.