I get this, but I prefer this tradeoff instead of the browser unloading something I wanted to keep loaded.
When I start Firefox, most tabs (4 or 5 nowadays) won't load, but be there as placeholders for things I need/want to solve through the week (e.g., Amazon search for a gift for my nephew, Youtube list of tutorials). They won't load until I'm ready to use those tabs.
On the other hand, I've had tabs loaded from the start of one session and used sparsely through the day. I would not want those tabs to be unloaded without my consent, even if they are memory hogs, as it would interrupt my workflow. Crashing is fine (and accepted as a last moment failsafe move) by me.
