You're Not Going To Try And Upsell Performance To A Client... The Same Should Really Go For Accessibility
"If you practice proper web centred (web native) design and use the technology the way it was intended and designed to be used, you generally create accessible things; accessibility is built in such a way that you don't have to spend much time making a separate process for it.
You're not going to try and upsell performance to a client... you wouldn't want to put off people using your site in that way. The same should really go for accessibility."