Subscription services like Netflix are cheap. Vastly cheaper than Safari. Furthermore, Netflix allows two viewing streams simultaneously, 24 hours a day, and all five members of my household have their own profiles. We almost certainly spend more hours as a family on Netflix than we do reading O'Reilly books (especially since it's mostly just me who does that, and sometimes my son when we're doing programming together).
I'm not spending $399/year. Maybe if it were $8/month like I spend on Netflix and Crunchyroll or Amazon Prime (paid annually), sure. (Granted, this household uses Prime for delivery and ignore their streaming stuff mostly.)
Goodbye O'Reilly. Not only will I not buy Safari, I will not buy any O'Reilly product ever again.