We, and especially Riley, have commented on this for years. Here is a succinct summary of the problems encountered by blind users, along with some information on remediation and tools available.
I was recently asked to re-write a web site to increase usability for the visually challenged. I had to turn it down. Why? Well, most of us who do HTML and derivatives never thought about the blind and so we did our sites in such a way that simply inserting "ALT" tags would do nothing to improve accessibility. Sites need to be designed for accessibility from the start. Once that is done, improving accessibility is really not that much work and surely not inconvenient beyond the needed labor. The site I was being asked to work on really needed to be completely redone, not just tarted up for the blind. Too big a job for the likes of me.