To be honest, I think a focus on gui actually inhibits future users. Especially in the linux world.
I use Linux Mint. I get 90% of my tech support questions from ubuntu based sites because of the greater sized community. The gui is nothing similar. However, below that very superficial layer, linux mint and ubuntu are exceptionally similar. That means that if it works in ubuntu, it'll work in linux mint.
If everyone send out gui commands, suddenly I would need separate instructions for linux mint, and for that matter, users of lxde, xfce, peppermint, debian, ubuntu studio, etc, etc, etc. Now lets start on arch and their many derivatives, fedora... free bsd, open bsd... (don't get me started that some of these are desktop environments and others are actual separate distro's. you can have a kde and xfce and lxde in gnome or fedora or debian or ubuntu)
The terminal unites us, it is a common layer between pretty much all *nixes and *bsd.
Sure, there are differences, package managers, boot up sequences and other differences (location and default setups of config files, etc) that will set you back a bit. But for the most part, it's pretty much the same (I'm sure there are distro proud people who will heartfully disagree with this).
As for efficiency, it's true that the gui is faster... for new or barely proficient users. This isn't a smack against those people, everyone has to be new sometimes and for those barely proficient, that's often enough to get by.
But gui only limits your potential, your productivity and relevance to the future versions of whatever you're working on.
If people are telling you different, my suspicion is they only have a rudimentary understanding of the terminal, have a limited imagination (using the terminal has inspired me to write some very clever commands to achieve goals impossible in gui) or are plain stuck in their ways that gui is the way to go because it's the way to go.