out with 95% effectiveness against the "Wild Type", or "Alpha" version...but then, along came the "Delta" variant and the efficiency dropped...not to zero...but to somewhere in the range of 64-69%...meaning that the vaccines still protected against any infection for that proportion of the community...and of course, the protection from serious illness (the most important benefit) has remained very high.
The CDC changes in mask requirements followed the rise of the Delta variant...pretty straight-forward.
If you really want to get back to a pre-pandemic life, keep telling everyone you know to get vaccinated and follow CDC guidelines...