SSO Tax
ssotax.org
ssotax.org
For some of those services it might not be profitable with there cheapest plans.
There certainly is price gauging from some vendors, but it's not unreasonable to charge a premium.
Supporting a narrow particular set of vendors (Azure OIDC and Okta, OIDC/SAML2) is dirt cheap. LDAP is another story and a real enterprise from support standpoint. Every time it's a support case with a high chance to allocate an engineer to solve the issue. I bet most of listed services don't support LDAP.
BTW. I have no issues with the pricing policy. You ask price others are ready to pay.
Also it could be an opportunity to eval other products with SSO from the box.