Follower count is the metric everyone watches because it's public, it goes up, and it feels like progress. It's also nearly useless as a measure of a business. Plenty of large accounts earn nothing; plenty of small ones earn well. The number flatters you without informing you.
Watch what money touches
The honest metrics are the ones connected to income: how many people reach your page, how many act, how much each visitor is worth. These are less fun to check and far more useful. They tell you what's working; followers only tell you that you're visible.
Don't optimise the vanity number
Chasing followers can actively hurt you — broad, shallow reach that never buys. A smaller audience of the right people beats a huge one of the wrong ones. Grow the number that pays, not the one that impresses.