Google shutting down their RSS reader didn't really have an impact.

They shut it down back in March of 2013. If you look at the trends graph[1] for RSS it was dying out for years.

[1] https://trends.google.com/trends/explore?date=all&q=%2Fm%2F0...

Long-term Google trends graphs are kind of useless because they're a percentage of queries over a period of time when the demographics of the user base was changing as millions of new people got on the internet.

Here's the one for javascript:

https://trends.google.com/trends/explore?date=all&q=javascri...

Clearly javascript has been slowly dying out. But wait, that can't be right.

They're also a poor proxy for usage because the existing user base with feeds already set up doesn't have to do a search query to continue using it, so if a large number of them lose access at once, it's barely a blip because they wouldn't be doing searches for it either way.

Do you know a better alternative? I would like to know

You probably didn't want to come across this way, but we should note that the absence of a better metric is not by itself a reason to use a bad one.

If a metric is sufficiently decorrelated with the thing we want to measure, it should be ignored altogether, regardless of whether we have anything better.