1. The survey found that only 63.8% said their job required a home internet connection pre pandemic, so it's closer to 40% of Americans with jobs that don't require home internet.
2. Sending emails from your phone at home is for all intents and purposes the same as a home internet connection. If you were no longer able to connect to the internet from within your home, you wouldn't be able to send those emails i.e. do your job.
3. There is a difference between jobs that can theoretically be done without home internet access, but that in practice require it. For example, you could theoretically drive a truck without any home internet. But, in practice, most truckers find loads and contracts via load boards, which you obviously need an internet connection to access.
With all of those considerations, the percentages don't seem too fishy to me. I buy that pre-pandemic, roughly 64% of Americans were in jobs that required them to connect to the internet from home for at least some work-related function, even if it is not the core of their work.