Largely this is probably true. One large benefit for the consumer with streaming music over buying it is actually that it is cheaper. Significantly cheaper if you listen to a bunch of different things. So if everyone has moved to a method of listening to music that costs less then there has to be less money available to artists (all else being equal).
Even if 100% of streaming services’ revenue went to artists it could still be less money.
The problem isn’t Spotify itself, it’s the business model of streaming being way too cheap.