This talk on YouTube by Tom Giardino from Valve goes over the state of Steam in 2018. He gives a lot of good information but in regards to Valve's decision to "open the floodgates" he shows these graphs:

From these graphs we can tell that Steam has been getting a higher amount of games succeeding over the years. Another interesting graph from the talk is this one:

And so based on these we know that more games have been succeeding on Steam than ever before, and that Steam users are buying more new games than ever before. The argument Indiepocalypsers always make is that as Steam opened up, it became harder to succeed. And even with those graphs you could still make that argument.

If in year 1 50 games made $100K in the first 30 days, and in year 5 100 games made $100K in the first 30 days, that seems like pretty good progress. But if the total number of games released in year 1 was 500 and the total number of games released in year 5 was 5000, we have a pretty drastic decrease in the percentage of successful games (from 10% to 2%).

So all things being equal, your chances of succeeding are lower in year 5 than they were in year 1. But this makes one big assumption, which is that all things are equal. If you're willing to concede that you're an average indie developer making average games then yes, based on this logic the Indiepocalypse is very real. If you don't consider that to be the case though then things are looking increasingly better :-)

For more on this I've written two relevant articles before: Luck Isn't Real and Hidden Gems Don't Exist