Until one of these alternatives is completely free like Google Analytics is I don't see a massive shift happening. I'm a web developer and there's no way I'd convince my clients to pay $20/month for something that Google offers for free.
We have lots of agencies who use us, and their clients may differ from yours, but here’s what’s helped them: https://usefathom.com/blog/switch
Just be aware that, while that is true for HN, and some subreddits, that still doesn't apply to most people. It's the same as saying, based on comments on HN, that people are moving away from Chrome when its market share is not going down.