No, I don’t believe leadership to be a thankless job. In fact, I believe leadership and management to be one of the most appreciated and fulfilling jobs out there. Why?
Because while some leadership/management tasks are thankless, the outcome are (hopefully) success and effectiveness. People are always happy to thank those who helped them be effective and successful.
If you are a manager and you believe your job to be thankless, you may not be in the right role or organization.
If you have a manager and think their job must be thankless, you may need to spend a bit more time in their shoes.