memory management
Banks use systems not meant for the internet? Show me a bank with a 10 year old computer and I'll show you a closed bank.
Computers manage their memory very well. As you say, it's ignorant programmers causing low memory problems. Windows is the worst I know of, loading unbelievable megabytes of unneeded applications on start.
Firefox does too, but it's how I have it set for my convenience. It's faster for me to restart when needed and have history available quickly. I love tabs and multiple windows!