Right. The root filesystem is a static image on purpose. You will lose anything that isn't in the persistent folder, including anything installed from the repos, after a reboot. I recommend running Whonix. It a little more secure than Tails because Tor is isolated in a separate VM, and it is persistent, so you can install additional software or upgrade Tor. The trade off is that that it isn't a leave-no-trace-behind OS like Tails. However, if an adversary has physical access to your hardware, the fact that you use Tor is the least of your problems. You can put Whonix and portable VirtualBox in an encrypted volume on a thumb drive and get close to the same privacy as Tails. There will probably be stuff in your log files indicating the times that you ran it.