This "rival" service is a paid-subscription and authors would still rely on Twitter for its audience to bring in subscribers. It's not replacing Twitter in anyway.

Twitter has a similar paid-subscription service called a "Super Follower" but, for whatever reason, not a lot of people use it.

Instead of asking why this is and how to fix this issue, Twitter soft bans Substack, even going so far as to label the links as "Unsafe/Malicious" to their users.

"My commitment to free speech extends even to not banning the account following my plane, even though that is a direct personal safety risk" - Elon Musk, shortly before banning the account following his plane

This "rival" service is a paid-subscription and authors would still rely on Twitter for its audience to bring in subscribers. It's not replacing Twitter in anyway.

Twitter has a similar paid-subscription service called a "Super Follower" but, for whatever reason, not a lot of people use it.

Instead of asking why this is and how to fix this issue, Twitter soft bans Substack, even going so far as to label the links as "Unsafe/Malicious" to their users.

"My commitment to free speech extends even to not banning the account following my plane, even though that is a direct personal safety risk" - Elon Musk, shortly before banning @elonjet