This is an answer from Mobil:

Thank you for your inquiry,

Sorry, but the TBN numbers for the gasoline Mobil1 engine motor oils
are not published, thus not available to the public.

--
Thank you for choosing ExxonMobil products.
If you need further assistance, please contact ExxonMobil at 1-800-ASK-MOBIL

WHY?

What is the most important thing to look before byuing an oil?
TBN? VI? Viscosity at 40 an 100 degrees? HSHT?