Many of us care about upload due to telecommuting as well as due to the increasing number of connected items at home, and the abundance of cloud services where uploading content is actually important. People certainly use upload whether they realize it or not. An example is that some of us might use Nest Cameras. These record to an off-site location (Which is a nice benefit, as thieves are wising up to SD Cards in cameras and local DVRs). Each camera at 1080P when there's motion, might consume close to 3Mbps of upload per. Several cameras with activity taking place would consume a considerable amount of bandwidth on the upload which will chew into the download, due to ACK starvation, and also because many connections like DOCSIS are not full duplex.
Now the perception between 10Mbps upload and 50Mbps upload might be big. The same goes for the difference between 50Mbps and 500Mbps. But it's enough to give the "Premium" feel that an ISP really wants to be known for. Offering poor upload but stupid fast download is not a way to do that.
My cable company tries to sell my Cable connection as Fiber connection. Sure... if you include the Fiber cabling which is delivering RFoG to my neighborhood. It's still not symmetrical, and it still doesn't have the latency that a Fiber connection provides. Stuff that people like I tend to care for. I had to pay Spectrum a mad amount of money just to get an extra 5Mbps up, so that my routine activities (video conference meetings) on Mondays don't consume my upload for hours. The upload is still rather inadequate at 10Mbps.
Given that backbone links are symmetrical in nature, it doesn't make sense to sell asymmetric connections just because people don't use the upload as much as the download. Both are equally as important, and make a difference in performance under load when the demand is actually there. It's the same concept of why 1Gbps or 2Gbps service is nice to have but isn't needed for most people right now.