Apple calendar stopped showing events on Mac

Indeed, it was a more wide-spread and general issue with Google.

However, I had opened a formal trouble ticket with them, which eventually got recognized, acknowledged, escalated, worked upon and resolved, by about 10:30 am PST 8/23/19.

However, you may need to still purge your calendar cache files:

• go to calendar.app, go to settings, go to accounts, uncheck the calendar to disable, then quit the calendar application.

• then, go to your User Library folder ( ~/library/calendars/ folder), (you can easily lookup how to do this if you don't know how to find it)

• then, delete all items with the name "Cache" in it such as: Calendar Cache-shm Calendar Cache Calendar Cache-wal

• go back to calendar.app, launch/run it, then, go to settings, go to accounts, check the calendar to re-enable your Google calendar account

• Then finally, you may wish to also click CMD-R to refresh calendar data and wait for enough time for all data to re-sync

It is a general issue, not clear if it is on Mac or Google side: https://support.google.com/calendar/thread/12612472?hl=en