People do care, but there are so many problems in the world, and only so much caring to go around.

It's extremely cynical to view it as "people pretend to care", rather than looking around and realizing there's a ton of important problems out there that the caring is distributed over. People care about disabilities, but they also care about war, about public schooling, about the environment, about feminism, about animal rights, about transparency in government, about road safety, about child well-being, about unemployment, and so on. All of these are important things, and of course there are dozens more that I haven't listed.

And inventions are sometimes actually useful. Sure, most of those prototypes will go nowhere, but every once in a while something that really helps is invented. And you can't predict in advance only the ones that will actually go on to help.