The argument that an equalizer before the loudspeaker (and amplifier) is parasitic is a big discussion. Loudspeakers are "systems" and it is widely accepted that a "parasitic" circuit, the crossover, is an integral part of any multi-way loudspeaker.
In addition to loudspeaker alignments that are passively tuned, like the sealed enclosure or the ported enclosure, each with their "natural" cutoff slopes in the low frequencies that are reached by the interaction of the woofer properties and enclosure / port dimensions, there are "assisted" alignments that utilize active parts.
My experience is with the KEF 107. The 4th order bandpass design utilizes a sealed rear chamber of relatively small size for a driver. The woofers in the KEF 107 could be optimally used in a sealed enclosure (1st order) of twice or three times the size.
Because of the small enclosure in this design, the excursion of the woofer is much better controlled and through equalization, the low frequencies can be (carefully) augmented to achieve a much flatter response further lower in the frequency before the cuttoff. It is much better to equalize high the low frequencies you want to enhance rather than passively attenuate the higher low frequencies. A much lower power amplifier will be needed, no power will be lost in passive components and all becomes more feasible.
I agree that all is highly unusual and not much exploited, but that doesn't mean it's wrong or useless.