Foot in mouth ~ in this day in age?

I try not to put my foot in my mouth, not that I could literally do such a thing at my age.  I'm no longer as agile as this baby.  To put one's foot in one's mouth means to say something foolish, embarrassing, or tactless:  "Charlotte put her foot in her mouth when she called him by her first husband's name."  Read this article (where I found the photo) for what to say and do when you have put your foot in your mouth.

The basis for writing this post about words was something garbled on Facebook about "this day in age."  Read it carefully:  "day in age."  What does that even mean?  It should be "this day and age."  Grammarly says:

Simply put, “in this day and age” means “now, at the present time.”  An age is a period of time, such as the Middle Ages, the Axial Age, or the Dark Ages.  While those times are all in the past, “this day and age” refers to the current time — “this day.”  Remember, a day is not necessarily a 24-hour period of time.

Obviously, the person on Facebook heard "in" rather than "and" in the phrase.  And remember, we aren't talking about my age (78) or your age.  We're talking about NOW.  Right now.  This period of time.