The reasons Spotify gives:
- A larger percentage of their customers live in countries with lower subscriptions prices.
- They have a free, ad-supported tier, that pays lower rates.
- Their average customer listens to more streams per month than the average Apple Music listener.
Both services claim similar revenue sharing. If a customer from the US paid Spotify $10.99 for a Apple Music subscription, and $10.99 for a Spotify subscription (recently increased to $11.99), a similar dollar amount from each service would be passed on to the rights holders. Maybe some of the shenanigans with bundle pricing or whatever changes the Spotify cut somewhat, but not enough to make a 3x difference.
If you were to say "Subscribe to Apple Music instead of Spotify, because 3 times as much of your money will go to the artists you like", that would be false. To be clear, I'm not claiming you said that, but I think the claims of 30% and 3x are deceptive without context.