Yep. At least steel and aluminum (ooo titanium) can be produced, & recycled, using electric arc furnaces.

That's what i always find funny. i mean i like stuff like that, i currently have a carbon frame mtb that i absolutely adore. I bought the frame for cheap and build the bike from parts that i already had. But i don't think there is any advantage. It's not even very light, i just like the idea of it. I sometimes talk to ebike enthusiasts who own 10+K ebikes with carbon frames. Good job, you saved 500g on a 22kg bike where the battery and the motor is the thing that weights it down. And the guys are always on the chunky side as well. Bro, you van drop 10kg easily.

The issue is not weight. You are not competing anyway to desire those few minutes off. Problem with carbon is that it fails critically. With aluminium and its alloys if you hit the frame somewhere bike is most likely going to be fine. With carbon chances of complete failure are higher.

So carbon frames are somewhat softer and provide more enjoyable ride. However carbon is not as resistant to damage as is metal. If it fails, chances are it will fail completely while with aluminium frame you can easily fix a dent and keep moving or not even address the damage at all. My bike for example has best of both worlds, aluminium frame and carbon forks. That way I get some smoothing during ride but most of the bike is aluminium, so a middle ground.

How does it stack up? It's like switching from 50cc scooter to 650cc sport bike. It simply can't compare. Carbon has very little to do with that really, but 50$ bike from a store would assume poorer transmission and general quality which means higher weight. Lower weight goes faster, thinner tires go faster, good transmission means you go faster. In general both bikes will get you from point A to point B, but being able to travel faster than 30km/h on your own strength is a feeling to be experienced. It feels very fast and satisfying.

As someone who switched from a Walmart bike to a carbon fiber bike I can definitely say there's a huge difference. Everything on the carbon fiber one is much higher quality. The gear ratios is has make sense, whereas I could never find the right ratios on the cheap one. Switching speeds is much faster too as I can be pedaling hard while changing gears and I know it's going to do exactly what I tell it. Finding parts is very easy compared to the Walmart one. Anytime something broke on the old one it was difficult or impossible to find a replacement. With a much nicer bike you can get parts for it easily so I can keep it in top shape for a long time. There are many other benefits as well.

I'd argue for aluminum only for the resistance to corrosion. I rode through snow and salt all winter in NYC; while I'd rinse the bike off right after, there's still holes and nooks in the frame.

Only issues with fixie bikes I have is the strain on your knees and ligaments they make.

I work in a bike shop and my colleagues like to poke fun at my 13" kids mountain bike that I use to commute. But you know what, over 3 years, even after riding over glass bottles and thorny branches and who knows what, no puncture so far. All I've had to do is change my brake cable, just did a chain and freewheel replacement last week (probably cos I don't wash it as often as I should) and a brake pad replacement cos the ones it came with on the v brake was the cheap sort that screamed.

They keep telling me to upgrade to a aluminium frame hybrid, I'm like, why?

What side of comparisons are being made? I own two enthusiast level carbon fiber bikes but also have a steel framed urban bike and love them all.

Less people steal steel than carbon, I'd assume.

Does carbon have the same longevity and load characteristics as steel?

Yeah weight is the best advantage for carbon imo. Of course when you're riding it's a marginal performance gain nobody really needs nor want. But when you're not it's a massive difference. Try going up a tight spiral staircase to reach you front door with a 25lbs roadie. Now do that twice a day to commute to work and suddenly the steel part really, really sucks. Even more recent options are still 50% heavier not to mention as expensive as some cheaper CF options, not all of them are 10k. Aluminium is really the only good alternative as far as I'm concerned.

And they also think looks is a valid argument.

You don’t even need to spend 10k to get a carbon bike anymore, they start under 3k

I got my cyclo-cross on sale for < $1,500.

I love that I can easily lift and carry it.

No regrets. (Other than getting fibromyalgia 6 months after buying it lol).