Of course it is not the same the
That is why i said sort of maybe band eq is a more appropriate expression. If you have nulls the end result is the same you can not deal with these with DSP also.
It really isn't clear what you are trying to achieve. Nobody has suggested anything about room nulls. Everyone knows they can't be fixed with EQ, so they are never part of the conversation.
A crossover's job is as the name says - to crossover between drivers. The slopes, turnover points, and special tweaking of sections are designed to work with the specific drivers and cabinet design. Changing the gain on one driver throws a heap of careful design out the window. Any good speaker will have some hidden optimisation in the crossover design, optimisations that will not be obvious. And correct operation depends upon the exact relative output of the different drivers. No crossover is brick-wall, and the out of band response must, and is, considered when considering the overall response of the speaker. In the extreme, if you have a second order crossover all hell breaks loose if the gain is changed.
There seems to a set of rather dated idea and some very specific poor experience with DSP here that is driving a desire for a very specific and unusual (to say the least) approach to system design. It isn't as if this stuff is new or controversial. It is extraordinarily unlikely that varying from the default case of DSP all the way to DACs for with digital volume will not yield the best possible final result. Given a competent modern DAC of almost any price, any noise or distortion products will always be below audibility. Strange hybrid systems will inevitably just yield either a poorer result, or a result that costs more to implement to get the same performance. It was not always so, but the last few years have swung the balance firmly this way.
This isn't to say that it isn't easy to mess it up. We assume competent design. Perhaps, given the history of high-end audio this is not as safe an assumption as one might wish.