Wish it wasn't so rare to get good modding tools. From your examples, Valves commitment to their SDKs (for CS) and Warcraft's WorldEdit (DotA) are both nice ecosystems to work in.
It's tremendously sad. Modding scenes in various games were huge on-ramps to development, game and otherwise, for lots of big industry figures today. Where's that coming from for the next generation's when every product is locked down from factory to where DRM regularly cripples peoples PCs?
I'm certainly no huge name in industry, but my first experience with anything even resembling code was when I discovered you could edit the scenario files in Driver (1999) on the PC to give your car all kinds of weird abilities, change how the game ran, give yourself god mode, disable time limits, all kinds of stuff, just by changing the text in the files. And like, obviously that's not software development, but I was a little kid and that was my first experience of "if you change the files inside the program, it does different things!" and that was tremendously exciting for me at the time.
GTA 5 RP mod is big, Arma series are very bare bone games where modders created scenarios and game types. Both pubg and dayz comes from arma 2 mods.
Steam Workshop has made it easier than ever before, no need to run 3rd party launchers or visit a number of sketch websites to get your mods.
It's still rare to get modding tools from the developer though. Only a couple recent games I've played do that I've seen. Like Teardown for example