> Only works if the data I want is being replicated in many locations
Yes, the actual transfer won't be fetching from multiple sources unless it's replicated.
The difference between location-addressing and content-addressing is that it enables the content from being fetched from anywhere, which has uses outside of space too, as many storage solutions has already discovered since long time ago (multiple decades).
> SSD to cache or replicate data for others if I can possibly avoid it. That will unnecessarily shorten the lifetime of the SSD
Correct me if I'm wrong, but SSD lifetime is based on writes, not on reads. So you should be OK with replicating already saved data, in that case?
> that is such a hypothetical situation that I have absolutely no idea why it needs a real-world demonstration
The whole "IPFS in space" is a "utopia goal" of sorts, but aiming for it gives us benefits today.
Personally, I'd love to see a move from location-addressing to content-addressing as I'm often in locations with spotty global-internet connection and really poor latency. Sometimes, websites refuse to even try to serve me data, as it takes really long time for packets to go between where I am, and the host I'm trying to reach, so they decide to cut the connection as tell me "sorry, timed out..."
If the web was already built with content-addressing in mind, my machine could automatically fetch the content from another machine on my network, my neighbor, a dynamic cache at the ISP or wherever, anyone could serve me that data instead of that particular node with that particular IP on the other side of the world. Sharing a YouTube video between two computers on the same network would just transfer bytes on the local network, instead of reaching out to the internet. The benefits of this should be fairly obvious to anyone who is familiar with networking today.
Realistically, I don't think IPFS will be the technology that makes this possible in 10+ years, but that doesn't mean content-addressing itself is the reason why it isn't more widespread. Content-addressing been around for a long time already, and I'm sure even more and more people will realize its value over time.