The estate car dominated family transport for decades and has been almost entirely replaced by the crossover. The change was driven by seating height, regulation and margin rather than by capability.
A crossover is usually the same car raised
Most crossovers share their platform, engines and much of their structure with a hatchback or estate from the same manufacturer.
The differences are a raised ride height, revised suspension, taller body panels and additional cladding, none of which require a new engineering programme.
That makes the crossover an inexpensive derivative to develop while commanding a higher price, which is a compelling combination for a manufacturer.
Seating position turned out to matter more than boot space
Sitting higher improves the view over traffic, which drivers consistently report as feeling safer and less stressful even where the actual view is similar.
Getting in and out involves less bending, because the seat is closer to hip height. This matters to older buyers and to anyone fitting a child seat repeatedly.
An estate typically offers more usable luggage space than the crossover derived from the same car, and buyers have consistently traded that away.
The perception of safety runs ahead of the physics
A taller, heavier vehicle does offer some advantage in a collision with a smaller one, which is a real effect and part of why the segment grew.
A higher centre of gravity works the other way, and electronic stability control was the technology that made tall vehicles acceptably stable in emergency manoeuvres.
Once stability control became standard, the main dynamic objection to a raised vehicle largely disappeared, and the segment expanded quickly afterwards.
Regulation shaped the bodies as well
Pedestrian protection rules require space between the bonnet and hard components beneath it, which raised bonnet lines across the whole market.
A tall front is easier to style convincingly on a crossover than on a low estate, so the regulatory requirement suited one body style better than the other.
Crash structure requirements pushed sills and pillars thicker as well, and a taller body absorbs those changes with less compromise to visibility and headroom.
What was actually lost
Frontal area rose, and drag is proportional to it, so a crossover consumes more energy than the equivalent estate at motorway speed regardless of powertrain.
Load length suffers because the roof slopes and the tailgate is more upright, which affects anyone carrying long items rather than tall ones.
Handling is softer as a consequence of the raised centre of gravity, and the estate's advantage there remains, which is why the body style survives in performance forms.