Given a major security problem or a serious bug is reported for Struts 1 in near future, can we expect a new release with fixes?
As of now, actually no - that is what the EOL announcement essentially is about. Since the end of support is reached, you will either need to find mitigations, patch the existing Struts 1 source code yourself or migrate your project to another web framework.
... you should be aware that security and bug fixes will no longer be provided. If in future such flaws are found you will need to take action as described in the preceding answer.