Yes, that's the reason. If you know the work you do doesn't matter, you're going to get subpar results.
I won't speak for everyone, but the work I do doesn't matter. I do the work to get paid. The alternative is not get paid. I don't really have a choice. Something that I would consider matters more: building something with my hands like construction, electrician, trades, grocery workers, social services, train workers, factory workers, agricultural workers, bus drivers, etc. That stuff matters in my mind more than whatever widget I'm being paid to make. Those jobs are what keep society moving.
I suspect that for most people in tech, most of the work people do isn't benefiting society and the masses in a good way, it's just a way to make more money for other people. So, it's natural to not believe that their work matters. You have to convince yourself that it matters.
With that said, the solution is a restructure of society that encourages and reinforces work that people find meaningful. No little scrum standups will change any of that. If you truly believe that what you do is meaningful, then you'll get better results. Along those lines, you often hear the question, "What would you do if you didn't need a paycheck?"