I cannot speak to your Medicare plan specifically because your post is confusing as to what type of plan you might have BUT
If you have a Medicare Advantage Plan, the Center for Medicare & Medicaid Services (CMS) is trying to put through a rule on network adequacy that seems might address your concern about providers remaining on their list WAY past their professional retirement - perhaps, year after year for whatever the reason and where the breakdown lies. This won't be effective until next year but hopefully it will correct some of the problems with the network listing of providers. However, this will not fix providers leaving the network during the year for whatever the reason.
It is always best to check with any new provider's office on coverage under which they currently participate.
Here is part of the proposed CMS rule
CMS.gov - News Release 01/06/2022 - CY 2023 Medicare Advantage and Part D Proposed Rule
from the link:
Network Adequacy
To strengthen its application standards and oversight, CMS is proposing to require that plan applicants demonstrate they have a sufficient network of contracted providers to care for beneficiaries before CMS will approve an application for a new or expanded MA plan. We believe that requiring applicants to demonstrate compliance with network adequacy standards as part of the application process will strengthen our oversight of an organizationβs ability to provide an adequate network of providers to deliver care to MA enrollees.
In the meantime, if this is a real sticking point for you - go to the boss and voice your concerns, giving specifics- plan, providers listed who are no longer in service, customer service help complaints, etc., to Medicare (CMS). Medicare.gov - Filing complaints about your health or drug plan
It's Always Something . . . . Roseanna Roseannadanna