Many a language is created as a hobbie or test of skill and grows and grows.
The creator goes to work for a company and uses the language for some small internal tool.
Colleagues see it, take a look and try it.
Before you know the entire company is using it as one of their core languages.
People leave the company and go work elsewhere, sometimes taking the language with them.
That's how many languages grow, not by some diabolical plan to make our lives harder but by random drifting and connecting of neurons
Of course there are exceptions. Java was created specifically for the purpose of marketing it, and so was Visual Basic (for example) though that one was based on an older language that did start as I described.
Effectively, languages are evolving. Many current languages are natural progressions upon older ones. Dialects evolve, merge and die out over time as people add features creating their own versions of the language which either get abandoned or merged into the common codebase.
In Pascal there were several Object Oriented versions for example, all but one of which died out. The one that did survive did pick up some elements of the other dialects (as well as elements from other languages like C++).
I think the parallel between programming languages and natural languages can be drawn quite far, up to and including attempts to prevent "polution" of the language by "foreign elements" which with natural languages is typified by the French attempts to lock out any terms from other languages (remember last month's announcement to ban the word e-mail?).