I’ve always heard the closer the better due to pollination.Mine is Stowel evergreen.
https://migardener.com/products/stowell-evergreen-corn?_pos=13&_sid=5ec7960bf&_ss=r
I may have also planted too close together. Would it change anything if I thinned them? Cut them at the base or tried to pull some? I've never had corn not make ears at all. They're 7+ft tall now, perfect color leaves, fertilized on time and watered correctly.
I can't find anything on the Google machine about thinning late triggering other stalks grow ears... Ugh.
Has it been 80-100 days? If it has, I would pull.
From what I’ve read it could be weather (too hot and dry), soil (nutrients) or a virus .
Not sure if this helps. Is there a local college or group you could take a stalk to identify the problem?
https://www.gardeningknowhow.com/edible/vegetables/corn/corn-not-producing-ears.htm