I'm replaceable after all. If there is someone who is better and more effective at solving problems in some objectively good way - they should have my job. The only reason I still have it is because it seems this is hard to find. Employers are stuck with people who solve problems in the way they like for varying personal reasons and not the objectively best way of solving problems.
The hard part in keeping employees happy is that you can't just throw more money at them to make them effective. Keeping them stimulated is the difficult part. Some times you must accept that you must perhaps solve a problem that isn't the most critical one to address, or perhaps a bad call business wise, to keep employees happy, or keep them at all. I think a lot of the "Big rewrites" are in this category, for example. Not really a good idea compared to maintenance/improvement, but if the alternative is maintaining the old one _and_ lose the staff who could do that?