Why Does the Chazzan Repeat the Amidah?

 https://www.chabad.org/library/article_cdo/aid/3319017/jewish/Why-Does-the-Chazzan-Repeat-the-Amidah.htm

Why is the repetition said even when there may not be such people present?

The sages instituted that it be said after every Amidah,5 since otherwise we’d need to interrogate each individual in attendance to ascertain whether there is a congregant who fits the criteria for the repetition.6

Nowadays, virtually no one fits the criteria. But there is another reason for the repetition—we recite the Kedushah and Modim prayers during this time.7