It's possible symmetric encryption may never really be defeated by anything other than brute force. The exchange of the ephemeral key really is the important part, as you mention. Thankfully looks like we are getting closer to full adoption of post quantum TLS... but that doesn't help recorded communications before very recently. Scary thought.

Looks like 70% of cloudflare requests are using post-quantum TLS! https://radar.cloudflare.com/post-quantum