" economy" and "electric ajustment" are contradictory.
A self-contained ,mechanically -ajustable seat can be quickly removed or reconfigured, without the associated extra wiring-harness.
Consider worm/quadrant, Acme thread/split-nut , rack and pawl as three mechanisms that lend themselves to a rapid disengagement/reset as well as a slower,more progressive movement..
just my take on it, but the most important thing about a seat iscomfort
get that right and the range of fancy gimmicks ,hence the price, complexity and certification/maintenance costs can be reduced.
You cannot magic up space from nowhere . if it doesn't come from the space behind, it has to come from the "spare" space allocated to the seat's own occupant....that, in turn, creates a problem of access/egress for the pax between the seat in question and an obstruction (cabin-side of ajacent pax.)