If you were to actually pay a shop to do the maintenance, I suspect a bicycle would be more expensive per km than a car.
Maybe your carbon bike with expensive options to save every last gram of weight requires so much maintenance, but any proper Dutch city bike or bakfiets made of steel will last very long with minimal maintenance
So in some ways, the higher-end stuff can last a very long time.
Some brands (eg: Campy) provide for much better mid-level gear than others (SRAM), but it really depends on the model and the year. Old mid-tier Shimano gear (stx-rc / lx) used to last forever and be a very decent value offering, but times have changed somewhat.
Luckily the prevalence of eBikes is making strong and reliable gear available for us non-eBikers.
In the Before Times (pre-COVID) I cycled 5km to work and 5km back, rain or shine, every workday from March to December in Toronto, Canada.
Every spring I'd spend $100 on a tune up, which usually included a new chain, and every ~second year I'd need a new rear cassette too and some new brake pads too. I've had the same tyres for 10+ years (though I get flats 1-2 times per year so needed new tubes). I lubed the chain once a week from a bottle that I purchased for $10 which lasts for 1-2 years.
I have no idea where you get your bike maintenance ideas from, but my experience was quite different after a decade of experience.
Bikes in general do need some love. Especially: old bikes, cheap bikes, and heavily used ones: MTB and e-Bikes. They need a LOT of labour if you use them seriously, and bike shops just gouge the shit out of people. My local shop rate is $140 per hour ... for what is very often a sub-par to dangerous quality of work.
I do virtually all of my bike wrenching myself, because I grew up poor and didn't have a choice, and now I do it because I'm stubborn and like to know it's done properly. If I had to pay for all the work I've done, we're talking many 10's of thousands of dollars (I put a lot of MTB miles in). This just makes the whole affair unworkable to a lot of people.
Biking can be extremely economical, but good lord the average bike shop makes it hard. And the community just lets them get away with it, justifying insane markups and gouging by saying you have to support your LBS (this may be mostly astroturfing).
I assume it's also more important on e-bikes (and especially cargo e-bikes) since the chain sees higher forces over longer periods of time.
Not even close.
As other commenters have noted, lubing a chain is not especially challenging or expensive.
Which is essentially what most of the cargo bicycle market is right now.
Pushing it to a wider audience and expanding your users pushes the needle in one direction only: those less enthused about care and maintenance.
It also means less skilled riders, less common sense, more abuse, etc.
And if you want to open a business doing this as a service- you have 2 groups of clients: Cyclists and non-Cyclists who own bicycles.
I don't really want to imagine having to deal with either of those as my primary clients. For entirely different reasons. Unless I was charging absurd amounts.