Marsha, I can't think of another way to explain this.
This year, there are a number of people who are frail and ill, and probably elderly, and who will die over the next 12 months. Something will carry them off this year - flu or pneumonia or heart failure or Covid. Only one of them can. They will only die once.
If Covid becomes an endemic but generally well-treated respiratory disease, then it is the very elderly, the very ill, and those who have always had least resistance to respiratory viruses - and only these people - who will die. They will die of Covid rather than of flu, so the balance of 'cause of death of the very elderly or terminally ill' will change, but not the absolute numbers.
Some of the mitigations such as better ventilation, will reduce deaths from other infections. Other changes in society, such as increased wfh and a smaller amount of work-related travel se to the use of video conferencing, will reduce other causes of death such as traffic accidents.