Oh, totally, I am very well aware that most people don't care much about this, which also makes my outbound emails less private in turn. And the irony, I don't use Google myself, but my wife does, and even when I set up a new mailbox on a custom domain for her, she asked me to redirect it to her Gmail...but that's why we don't use plain text email for private stuff anymore.
What's your alternative to plain text email ?
Most of my family was using FB Messenger, but now it's WhatsApp, unfortunately still Meta, and I hate it, but at least it's encrypted and old messages are autodeleted. I couldn't convince them yet to use Signal or Matrix. Signal might work, I used to use it with my brother, but he was the only one, so wasn't really effective. I had hopes that I can move everyone to my own Matrix instance, but that looks unachievable right now. Edit: I forgot to mention calls, if something is very personal (not secret, just personal) we usually make call.