... given the fact that governments are recording everything for assessment and for looking at it when time comes later.
When time comes later, the information may still be recovered if the government is really really interested in finding out what it was that you wrote there, however it's going to be much more difficult than if it was plain text, there is nothing to recover with plain text, it's out in the open.
There are two scenarios here: either the government performs mitm attacks or they don't.
If they do perform mitm attacks, using an untrusted self-signed certificate is equivalent to using a CA-signed certificate in terms of what the govt can see. The govt can perform a mitm on the self-signed connectino by using their own self-signed cert, and the govt can perform a mitm on the CA-signed connection by forcing the CA to give up the CA cert and signing a new cert with the CA cert.
If they don't perform mitm attacks, the govt needs the website's cert to view the traffic. This means they either need foo.com's self-signed cert or bar.com's CA-signed cert. Either way, the CA's cert alone isn't good enough.
If you don't agree with those two scenarios, please explain which details are technically correct. (I'm fairly certain that none are.)
If you do agree, then it follows that you agree that using an untrusted self-signed cert is no better than using a CA-signed cert. The secure thing to do would be to use a trusted self-signed cert; that is, a self-signed cert whose fingerprint has been verified through a secure channel.
Saying that self signed certificates are worse than plain text is either propaganda for some ulterior motive or it is an irrational position, because the end user does NOT even have to be AWARE that a self signed certificate is used!
In fact if the browser doesn't even tell the user that there is a self signed certificate, then to the user it looks like a plain text connection and maybe that's how browsers really should treat self signed certificates that are not manually authorised by the user.
That browser user interface change would create a huge security hole. Consider the following scenario:
1. Alice, the user, accesses https://bank.com/ which uses a CA-signed certificate.
2. Mallory, an adversary, performs a mitm attack on Alice's connection. She replaces the CA-signed certificate with a self-signed certificate, allowing her to view all of Alice's traffic to bank.com.
With the current browser UIs, the browser would show Alice the self-signed certificate warning. Alice should see it, known she's under attack, and decide not to proceed.
With your proposed UI, the browser would show NO WARNING. Unless Alice knows that bank.com should display the HTTPS icon and notices that it isn't, she will proceed and Mallory will be able to view all of Alice's traffic.
It is COMPLETELY UNREASONABLE to expect Alice to notice that the HTTPS icon is missing. Many user studies have shown that users continue after seeing self-signed certificate warnings, which are impossible to miss and explicitly state the dangers of continuing.