But I believe any kind of side projects matter, at least they can help
pollinate other team members with new ideas and solutions....The closest explanation I can give to myself is that it's fear of rejection. They just don't want to broadcast the information about what they do, outside of work hours.
You might believe it's good for the company that your developers share their home projects with others. However, the developers themselves may believe just the opposite, and their reasons may be quite important to them, and have nothing to do with fear of rejection. For example:
- It's good for themselves not to share their home projects with the
company. Often such projects involve ideas and technology that a
developer may not be willing to share with the firm unless they are
duly compensated for it. They are paid to do their assigned work, not
contribute their own private time and hobby projects to the company.
- Such projects may also be seen as contingency plans in case things
don't go well at work, or paths to future projects or employment not
connected to your company. Bringing them into the office may compromise such plans or cause people to ask uncomfortable questions.
IMO your idea may not be entirely appropriate. I've been a code jockey for twenty years and never been in a situation where my bosses or co-workers were too interested in what I or others did on our own time, except in the most casual manner - friendly conversation, nothing more.
For many years I had my own side projects using technologies that weren't being used at work, and if my bosses would have started picking my brain about such things I would have been reluctant to share unless I knew that I would benefit from it at work. What did happen many times was that I was able to make contributions at work that I was compensated for because of knowledge and experience I had accumulated from my own home projects - I was able to advance because I was knowledgeable about the technologies I had been working with on my own, because they became relevant to projects at work. But I never voluntarily brought my home projects into the office to share.
This might not be "nice", but such is the nature of the business world: Developers are laborers for the firm that do work and receive compensation therefrom, not friends and family of their bosses and co-workers. We all know the hard, cold reality of business: A new boss or co-worker or merger or acquisition comes along, or you slip up badly somehow, and before you know it, you're out hunting for a new job. So, you keep your hobbies and private projects to yourself, just like any other aspect of your personal life that you don't share at work.
You've already mentioned that you have limitations due to management, etc. Perhaps you should be taking these limitations as a cue that your idea isn't such a good one.