Huh! I thought x86 Solaris was always free for personal use. I remember installing it on my desktop in 2003? I guess something might have changed in the past 20 years :V
It has remained free for test and dev use during the entire time Oracle owned it, yes. The big deal about this announcement is that it is still free for test and dev, but you get updates! Previously, you could get Solaris 11.4 from 2018, with no updates. Now you can get 11.4 with updates through December 2021, and it sounds like future updates will be made available.