Ask HN: Why 80 characters for titles?

Title editorialism is considered a faux-paux on HN, however, articles optimize their titles to fit in 140 characters due to Twitter and other similar platforms.

However, there are many titles that I feel I have made worse by shortening them to fit on HN (both having made it to the front page, and also not having made it).

Is there any real reason why HN doesn't switch to 140 as well?

Also, I feel shorter headlines leads towards more clickbait-like submissions making it to the front page.