"Should" is an impractical word. "Would" is better. One would trust a password manager as a result of their obvious social media login getting all their friend

"Should" is an impractical word. "Would" is better. One would trust a password manager as a result of their obvious social media login getting all their friends spammed. One would trust a password manager as a result of someone finding the post it documenting their bank credentials. One would trust a password manager as a result of missing out on an opportunity for forgetting a login and having to wait an ungodly number of hours due to an inconveniently timed DNS upgrade leading to a long delay in the password rest email's arrival. Nobody trusts password managers because of something essential to the password manager or the concept thereof, we trust password managers because we have experience or can imagine experiencing the fallout of our own credential mismanagement in the face of increasingly complex security demands resulting not always directly from increasingly sophisticated attacks. It reduces our cognitive load slightly and focuses otherwise diffuse anxieties.