This is a developing situation. See https://www.cbsnews.com/news/covid-19-variant-south-africa-spread/.

Video: https://filedn.com/lJ3YxkqPhCQJ55qtOyKrlSu/video/SouthAfricadetectsnewvariantcoronaviru...

Your points of:

A new variant could potentially go two dramatically different ways.

1. It makes all vaccines redundant and we're back at square one

2. It de-lethalizes the virus and solves the whole problem

You'd have to wonder with option 2 whether drug companies would ever allow that situation

Are worth emphasizing as these mutations occur. With the big money at play, including the stock market, how willing will "science" be to admit that the money sunk into the eradication efforts so far will yield less benefit than had been forecast into the markets?

EDIT: Assuming the vaccine becomes markedly less effective over the course of continued mutations, will governments and corporations continue to promote their use, and when pressed, use the excuse similar to the impotent social programs of WWII such as victory gardens and various means of frugality? Yet this time, the difference would be massive corporate profit.