This is exactly how I feel. Even though my income has quadrupled in the last three years I haven't made a single positive impact to anyone's life using my skills. This was a very sad realisation that I've basically been reinventing wheels for a living and not really engineering anything.
I find it hard to believe that someone would pay you a salary for three years to do something that is completely useless to everyone.
At the very minimum, the fruits of your labour are useful to your boss/customer. That is already a single positive impact in someone's life right there.
Most likely, your boss/customer then used your developments in their primary business, which, no doubt, affects even more people in a positive way.
I believe being in technology, we have the capability to positively affect many orders of magnitude more people, than in most other industries. So cheer up! ;)
I'd caution against making the argument "If someone pays you, it's useful to somebody." It reminds me of the naive assumption of economists, that people are rational and seek to maximize utility. But exceptions easily come to mind.
People waste money all the time. Maybe the OP's boss paid him three years salary to do something the boss thought was important, but really just wasted time. And nobody knew it wasted time, because it was hard to measure.
I agree. You may be "helping" your manager, but that may mean helping them displace their political opponent for the sole purpose of taking more power for themselves. That, and I've seen far too many inane requirements and heard too many stories of code that was never used to remain especially optimistic.
I agree with you, but I've been in situations where management continues wasteful projects because they can't admit failure, can't define goals for the project, or throw good money after bad. I should have been more specific.
A personal example: At a small marketing agency, my boss insisted we needed to offer social media marketing, since "everyone's on facebook now a days." Because we were posting on behalf of clients, we didn't have the expertise to write about the goings on of their business, and often had no contacts in the client organization. We were forced to write pretty generic stuff ("happy valentine's day everybody!" or "check out this news article"). Worse, we had clients who shouldn't be on social media in the first place: plumbers, dentists, and the like. I have never seen anyone like their plumber on facebook. So naturally, these pages were ghost towns.
Yet despite having zero likes and zero traffic, clients insisted on paying someone for social media (They too had read that "everyone's on facebook") and my boss never refused a paying customer.
Want to know how it feels getting paid day in and day out to make crap content that nobody will read? Feels bad.