I don't think we should necessarily aim to make "serious tools" easy for people to get into. I am not saying that the UI shouldn't be intuitive, but rather that making something 'too easy' results in low barriers to entry and you end up with the wrong types of people using that tool. Excel is very useful (I use it much in the same way the OP does), but it has it's limitations. Because it is so easy to get into, it's easy for individuals lacking the proper experience to over extend themselves.
I think much of the explosion in data science jobs these last few years isn't really about "big data", but rather the fact that your typical corporate analyst does not have the experience to tackle mid range data analysis jobs because the only tool they have under their belts is Excel. What really is needed is a larger number of people with experience in statistics, scientific computing (Python, R etc..), and database systems. The current tools we have are fine, they just need to be used properly (well, we should always strive to improve our tools, but you get the idea).
Excel is as ubiquitous as it is because the mental model of a spreadsheet is very simple and easy to wrap one's brain around. Here's a grid of cells, type stuff into them. Boom, you're an Excel user. (It can do a lot more than that, of course, but many many many people never realize that and still get lots of value out of it. Which is kind of remarkable, really.)
Proper databases are much more powerful, but none of them present the user with an interface whose basic metaphors are as immediately obvious as Excel's. You have to learn about tables, data types, relations, etc. to get anything done in them. Most of that stuff comes up with Excel too, but you don't need to know it to get started. The Excel user's first baby steps are much smaller than the database user's are.
Given a choice between a flawed tool that's immediately understandable and a perfect tool that requires learning, people will always choose the flawed-but-understandable tool. So they go with Excel.