People love to say this is due to regulation, but it really isn't. Safety regulations in the USA for automobiles are not terribly strict. It adds weight, for sure, but you can buy a 2100lb Mitsubishi Mirage with a stick shift. So mandatory safety aren't the biggest contributor to inflated curb weights.
Size inflation is predominantly driven by NVH and interior volume requirements from consumers. Dodge doesn't have to make the Challenger Hellcat a 4500lb two-door car. This car isn't fat for safety reasons, in fact, it score pretty damn low on safety tests.
Manufacture make heavy cars it because customers want gigantic, comfortable cruisers, with big engines, all-wheel job, 20" wheels on 265mm-wide tires, heavy duty lifted suspension, and full-length under-body trays.
Honda isn't immune to this, they don't even sell a car today that's as small in volume as your 88 Civic. The closest would be the discontinued CR-Z, which was a hyrbrid, or the no-long-sold-in-the-US Jazz/Fit, which is still quite a bit larger but only 2600lbs with a stickshift.
I love old Hondas, and you're right, they have a driving sensation that's impossible to get with modern cars. But don't blame regulations for Honda changing their ways, blame consumers. If people wanted a Civic with a 90hp engine, stick shift, four-wheel double-wishbone suspension, and 13" wheels, they'd sell one. Mitsu still does (for now).
People have said this exact thing for decades. It's because people old enough to remember being carted around in those cars as kids are finally getting old enough to be settled down and wealthy enough to have project cars. It has nothing to do with the vehicles themselves.
Within any given decade the things the rich kids got carted around in (or their dad commuted in) always command a premium.
Also, LiPo batteries can explode if you're not very careful with charge and discharge discipline. Even the small ones in cell phones can do significant damage that way.
Right now though we have some disappointing (from a power perspective) electric drivetrains from Prius' that can be swapped or a powerful but DRM'd Tesla drivetrain that is more work than it's worth.
A 1988 Honda Civic isn't purely mechanical. It still has an ECU, for example. It still relies on electrical sensors for basic operation.
> Car enthusiasts want that sweet spot of purely analog controls, but also with working factory A/C.
There's no shortage of new cars that still offer that, too, or recently used. You don't have to go back to the late-80s to get that. It seems to be mechanical steering combined with low curb weight that you're actually focusing on, which is still a market segment receiving new models. You've basically described every Porsche up until the 2012 model year, for example (when they first introduced electronic steering). Or the entire Lotus brand. Or specialty cars like the Alfa Romeo 4c, Toyota/Subaru FRS/GT86/BRZ, etc...
And, of course, you can't forget the king of sports cars - the Mazda Miata. 30 years later & it's still just as light as it's always been. And just as good.
> Something like a BMW M3 E30 would be a dream hobby car for me.
There's so much more to a car than spec sheets, and you should absolutely chase your dreams, but realize you can also basically buy a brand new M3 E30 today. The power, weight, size, etc... of the E30 is withing spitting distance of the GT86.
Both are front-engine rear-wheel drive. Both have manual transmissions (although a 6-speed in the GT86 vs. the 5-speed in the E30). Both have a ~2700lb curb weight. Both have a 101 in wheelbase. The 86 is a bit shorter length, bit shorter height, and a bit larger width, but all within a few inches. Both have a 4-cylinder engine at around 200hp, and both rev to about 7000 rpm. Both have responsive, playful suspensions, and direct steering feedback.
Regulations definitely didn't kill anything here as the same core specs still exist.
I am not enjoying having a computer constantly between me and the road. I also don't like the new lower bound for car weight due to all of the modern safety regulations. Even if you have a modern car with a ton of power, you can never truly compensate for the physics equation imposed by all of that weight.
For example: A 1988 Honda Civic weighs somewhere in the realm of 2000-2200 lbs. A 2020 model year weighs somewhere between 2700-3000 lbs. This makes a huge difference in how a car feels to drive, especially at extremes that are more likely to be explored by enthusiasts.
Something like a BMW M3 E30 would be a dream hobby car for me. There is a reason the 80s-90s model years are starting to go up in value. Car enthusiasts want that sweet spot of purely analog controls, but also with working factory A/C.