This is super SUPER annoying that this is not available. Especially for columns containing numbers, where you really don't want to take up a ton of unnecessary space, but are forced to because the column heads don't wrap. Anyway... you can install the Stylus Chrome Extension and then in the CSS box put in this code... and it will cause the text to be smaller and the text to wrap. It looks kind of dumb. But it works.
-moz-document domain("airtable.com") {
.text-size-default { font-size:9px; }
.headerRow .cell.read .contentWrapper .nameAndDescription { right:0; top:3px; }
.nameAndDescription .truncate { max-width:100%; overflow:visible; overflow-wrap:break-word; text-overflow:default; white-space:normal; }
}