This is right for most cases but your notion of ground switched lighting is wrong. What we are talking about is this
Standard Way: B+ ----- HDLP Switch ---- Dimmer Switch ----- High beams --- GND |------- Low beams --- GND
Ground Switched
B+ ----- High Beams ---- Dimmer Switch --- HDLP Switch --- GND ----- Low Beams -----|
Note that in standard way B+ has to enter passenger compartment, go through switches, then back out to headlamps. In ground switched way, b+ goes through lights, into passenger compartment, through switches, and into ground. No looping.
Also note that the current through the switches in ground-switched setup is always limited by what passes through the bulbs, even if there is a short to ground somewhere. Unfortunately this means a short to ground wont blow a fuse but instead make the lights permanently on.
There are tradeoffs and both systems are in use today but most still use the Standard way. (Well except high end cars which tend to have low current headlamp switch and control the lights through relays and/or FETs... Lots of your cars with daytime running lamps will do that, as well as cars with autolamps)