There are no warning signs.
The US is shutting down processors just like they have done every so often for the last several years. Many books are choosing to no longer take US customers but are not turning away existing customers, this is because they are happy with their current customer base and the less US players depositing $50 at a time the less issues books will have with processors.
Nobody is running away from the US market most are just choosing to limit their exposure.
If you are scared to play than run along but don't try desperately to convince others to follow you just because you are over thinking things.
Nobody cares if the world is going to end tomorrow
don't worry about the rest of us just save yourself.