Why can't I see all the comments on my posts in the Thai visa advice Facebook group?

Try to click timestamp of your post. Not sure for your case, but In some cases this works as workaround.

But this was the answer by Tod Daniels: I have never seen someone go from an extension of stay based on employment to one based on retirement inside the country.

In theory there is nothing prohibiting it because as you said all you're doing is changing the reason for your extension from work to being over 50 (retirement).

You would have to have documentation from your company stating on xxx date you are stopping work, you would cancel your work permit and take that receipt and the termination paperwork from your company to the immigration office, cancel your current extension based on employment and immediately apply for a new yearly extension based on being over 50 by meeting the financial requirements of 800K baht in a thai bank account in your name only for 60 days prior to your application, a notarized affidavit of income from abroad from your consulate stating you get at least 65K baht a month in income or a combination of banked money and the notary document that totals 800K baht for the year.

IF you try it and it works please report back :)

And the third

Just to help, he can not see the first three.

There is no such rule of long time members are allowed to read all the comments. It must be a facebook thing.