That's not the entire truth. It might be the theory of the concept, but the practical reality is different. If I send my navigation app to the background, it keeps running and talking and sucking energy. Need to close it. Also mail keeps making pling at every incoming email. Reminders indicates gps useage unless it's propperly closed. And I believe there are more.
You are just mischaracterizing the actual situation in your description of "practical reality".
Navigation continues running in the background because it is navigating! No need to close it. Just clear the route. That's kinda like complaining that you have music playing in the background when all you need to do is hit the pause button.
Mail will continue to check for Mail even if you quit the app from the tray.
Reminders only uses GPS if you created a location based reminder. Which functions even if the Reminders app is "properly closed."