What motivates people to take pictures and upload them to the internet? You don't have to be well paid, photo sites with billions of photos that don't pay anything are proof of that. So is microstock more than just the royalties? YES!
Over and above simply 'enjoying photography', social aspects of microstock (depending on what you shoot) there is usually a mix of different incentives and motivations that spur individual photographers to upload, share or sell their images online:
Depending on your level of microstock experience you are likely to view 'recognition' as something that 'amateurs' enjoy more than a primary microstock motivator. It is true that peer recognition is primarily the realm of social network photo sharing (flickr, tumblr, blogging etc) or news and media sites touting for 'free' photos. Almost all microstock sites display statistics about uploads in your profile, time online, sometimes sales info etc, there's not much kudos in this, but I feel it's definitely a driver to improve your ranking.
Look at the forums and you'll see some photographers just people love sharing their stats and bragging about successful shoots they have been involved in. Plenty of photographers also collect or post clipping sheets (digital versions of) when they see their images being published.
Wow you can get paid for doing what you love doing?... If I put my cynical hat on, depending on your background and level of education it's quite likely you can get paid much more for your time doing something else! It's unlikely money is the main driver that gets photographers into microstock (if not into photography in general!). Perhaps it is the smell of money that motivates? e.g. my earnings will be higher if I upload more, rather than the actual dollar amount of value each image generates?
Continued self-improvement and moving forward through a growing microstock business is certainly high on my list of motivators, I'd suggest the same for my life in general! The same applies to any job, on analysis the mix is surprisingly difficult to make sense of: ranging from a mere illusion of growth through to constantly pushing yourself out of your comfort zone for the better
Is flexible working time, being your own boss, sustainable income rather than money for time etc "a motivation"? If it's not a motivator, it's certainly a lack of demotivation. As plenty of microstockers work in their spare time I'm not sure how this fits into the big picture, perhaps a light at the end of the tunnel; something to focus on or distract yourself during a day in the cube farm?
I know for myself and from listening to others that there is a lot of motivation in knowing you are completing a goal you have set yourself; and even just at the end of the day siting back and looking at the images you have been able to create. There is something satisfying about looking at your own portfolio from time to time, you might work with your images every day but just now and again stand back and look at them as a collection. I'll close this post with a favourite Thatcherism "Look at a day when you are supremely satisfied at the end. It's not a day when you lounge around doing nothing; it's a day you've had everything to do and you've done it."
What motivates you?