A lot of effort has been put in the design of interfaces which are simple to use, and people who try to sell computer products or services to you will usually present that as one of their main selling points. However, when you think of it, there really aren't that many people who try to create interfaces which are efficient, and efficiency doesn't sell at all.
This seems quite surprising. Simplicity and efficiency are usually two contradictory aims. For instance, it is usually faster to hit a key than to click a button (hence keyboard shortcuts), but you have to learn which key is mapped to which command, whereas buttons have labels which allow you to find out which one to click; displaying help messages take up screen space which is wasted for those users who already know how things work.
I am not saying that efficiency should always be favoured over simplicity. For tasks that you don't do very often, it wouldn't be worthwhile to spend the time required to learn an efficient interface. However, for tasks which you often do and which you will keep doing for quite some time (in my case: writing text, answering email, coding, etc.), learning how to use efficient tools is a profitable investment.
It is tempting to say that it makes more sense commercially to favour simplicity over efficiency because your product or service will have more casual users than hardcore users. This may be true, but it's not the whole story. Expert users are usually willing to pay more, and tend to influence other people, which makes it profitable to try to seduce them. Furthermore, outside of the computing world, things aren't always done that way. Piano keys don't carry labels, even though this could be useful for beginners. Bicycles aren't sold with the little stabilizer wheels you sometimes see on bikes for young children. Yet, webmails, social networking websites, operating systems and mobile phones usually have an interface which is simple but crippled, and that doesn't seem to bother in the slightest the numerous people who use them several hours per week...
I think that in fact, while the number of people who should theoretically invest time to learn efficient solutions is large enough, the number of people who are conscious of that need is much smaller. That's probably because society hasn't realized yet the quantity of time that people tend to spend on their computers, as compared to the time where computers weren't ubiquitous and where very few people used them. It's probably also because people tend to act irrationally and are unwilling to spend some time learning and recoup their investment later. Or perhaps because they are unwilling to acknowledge the time they spend on their computer, because they think it was somehow wasted.