Exactly what specialized tools do you need to work on a car? Are you counting closed end wrenches and sockets as "specialized" or something?
Otherwise, doing routine/basic maintenance on a car, such as changing the oil, requires a means of getting under the car (ramps or jack and stands) and of handling large amounts of fluids (drain pan and funnel) neither of which you need to do the equivalent work on a bike.
A torque wrench is much more important for car maintenance than for bike maintenance (and you'll need a bigger one!). Depending on the condition of your car you may want a breaker bar.
Obviously doing anything with the suspension requires a spring compressor, and troubleshooting certain engine problems requires a compression tester, but those are needed infrequently enough that they can be rented or borrowed.
And that's before getting into the model-specific specialized tools for something like a timing belt change, or anything electronic (though I recommend anyone with a car should get a cheap Bluetooth OBDII reader).
Manual for my latest car recommends against jacking up under the front axle, so a jack and stands are out for getting underneath it.
A torque wrench is a specialized tool...for torquing a fastener. I use the torque wrench to torque fasteners on my truck, my motorcycle, some random piece of equipment I want to repair, etc.
I have seal drivers for driving seals on my motorcycle. I also can use them on hydraulic cylinders, or any other random seal I want to drive in.
The only truly specialized piece of auto repair tooling I have is a tool that is cast and machined specifically to fit inside the engine head to remove a portion of the valvetrain for maintenance. It's a very boring once you understand how it works, but I'm not using it for anything else.
As for a spring compressor, I've been doing suspension work for about a decade now and used one zero times. You just don't need it for routine maintenance. I guess if a spring breaks, you would need it in some weird circumstance possibly.
Various BB tools, also for disc brake lockrings
Chain whip
Bleed kit
You can force a missing link with other tools but the dedicated pliers are really much better
And a chain whip, and a lockring bit for brakes/cassette, and another bit for the bottom bracket, and some pin spanners maybe, a derailer alignment gauge, maybe crank puller, tire levers, chain breaker, and master link pliers. Hydraulic brakes? Bleed kit, piston press. Pneumatic suspension? Shock pump. Tubeless? Better get a syringe to refill sealant through valves (and don't forget the valve core wrench) or reset your tires every time you need new sealant.
For someone who owns a car and nothing else with an internal combustion engine except maybe a lawnmower, most of those tools are only used to work on their car.
There are of course also specialized tools you need to work on a bicycle- tire levers and a chain link breaker, for instance. But they're much smaller and cheaper.
He said this sort of thing is getting more common and even if he did want to buy all of the required bits and bobs he wouldn't be able to fit them all in his van.
Even in the 'good old days', you weren't getting very far working on your car without things like gear pullers, timing guns and feeler gauges. All things that technically you could be using for other things, but not exactly in the average toolbox of someone that doesn't work on cars.