I think it's because while he certainly wasn't the first to come up with spatial / furniture-y music - with Ambient 1 he officially coined "ambient" as a genre name (as a brand, as it were), by all accounts. That album was also probably the first introduction that kind of music for a great many people. It certainly was for me.

Also, like the iPod or iPhone, they weren't the first but they did set the standard for the product category. Ambient 1 is the same for ambient music.

I think I discovered him when listening to the ambient station on di.fm (digitally imported). Perhaps he gained a following from that?

They are also great pop albums. A ton of memorable tunes in a surprisingly accessible format.

I discovered him through Coldplay. I can't remember which ones but he produced at least one of the early records.

I'd suspect most people are aware of him as some tangential element to a band or bands that are far better known:

Bowie, Talking Heads, Devo, U2 ... almost all of it getting some subtle Eno flavor. He never struck me as overbearing or obvious on his work, generally just adding a little bit of him on top of whoever he was producing/working with.

Here I'll admit that I think Another Green World starts really strong and falls off. It's a beloved album but I'll happily take my downvotes in preferring HCTWJ.

I bought HCTWJ first but Another Green World is the one I really wore out the grooves on. And I think the ambient stuff after that is so-so.