As usual, Tom has described it very well. The "easy" and its repackaged clones (including the Logo, AB Pico, and many others) fill a need in the industry.
Back over ten years ago, the GE Smart Relay tried, in a slightly different form, more of a true programmable relay.
Unfortunately, some of the new "easy" type products are getting a little to pricey. Granted, you can shop online and find them under $100. You can get some fancier ones for a few hunderd.
You can also get a real PLC for a couple of hundred, and have a lot more capabilities. Entertron has the SmartPak series, AD has a couple of models, and other manufactuers too! Heck, you can even get a small AB for $99.
EZ's rack system is dirt cheap. I doubt I will ever use one, and don't know of anyone anywhere who has, to date. But they are cheap.
You can get a Logo, and it has built in software, to an extent. A stand alone PLC is stand alone, but you will have to support or assist it with an external programmer of some sort.
It sounds like the Logo, "easy", Pico, or whatever is more what you want, with it's built in programming capabilities.