Can our position or person be easily replaced in the office?
Look at this face. Would it be possible to replace Kevin with his excellent reflexes, sympathetic ear, and consistent routine? Perhaps if the neighbours house is more fun he may pack his litterbox and leave. We may get a new cat, or upgrade to a kitten. Or we may throw caution out-the-door and get a dog. Kevin's unique personality and big paws would be missed but we would carry-on. (Note: Kevin is a little more than a co-worker relationship but the analogy still has value.)
As with the office, when we leave, we can be replaced. Our position my change or someone new may come and continue our role, but the company will not go under because we left. Yes, when a hardworking and qualified individual does leave it can take time and money to get projects back-on-track, but the work will still get done somehow. The work may not get done as well as your performance on the project, or it may not be as efficient, however, a company will continue to operate.
Good leadership values teams that work hard and team members that produce good product. These leaders try to make individuals feel like they are bonafide contributors to projects and the firm so that they don't need to look elsewhere for employment. If you are disgruntled with your position and feeling undervalued - you are not alone. There is a lack of leadership in many companies which is difficult to change. Unfortunately, if you leave, it will not cause the company to collapse. It is best to converse with leadership about feeling undervalued and if they can't help you, or do not offer support for you to feel valued, then leave for your own self-recognition and not because you want to screw the company.
There are instances where a very valued individual does leave and the leadership at the top is not strong enough to keep the ship sailing. The downfall of the company can be slow and messy as new team members will not join the company or the company can't continually retain good quality staff.
The employee and employer relationship should be equal - you are helping the company by offering your talents and in exchange the employer is paying you for your skills. Both need to be treated fairly and ethically.
Do your job well for your own integrity, then the worry about being replaced is unnecessary!
Fiona Warren - 17 years experience with large high-profile projects and teams.