The typos have been theorized to be intentional (for that reason), but that isn’t the only theory, and afaik those theories aren’t based off conversations with the people crafting those emails.

It’s also been theorized that phishing emails frequently have typos (intentionally) to lower people’s resistance to well-crafted phishing emails, particular spear phishing.

There’s also the fact that many phishing emails are crafted by people for whom English is not their first language, and even given that, phishing emails are still better written than spam emails, so it’s quite likely that in many cases it isn’t intentional at all.