If not, is it because Western languages are somehow intrinsically simpler, or because the political willpower did not exist?

To start, Western languages are not intrinsically simpler. The idea that a natural language is objectively simpler than another natural language isn't an accepted one in linguistics. There's a balance between simplicity and complexity and when languages become more simple in some area, they tend to be more complex in other areas. Simplicity overall isn't really sustainable, which is why you see this first generation of native^1 Esperanto speakers adding complexity that the purists don't like.

The ways in which Mandarin is complex is primarily the orthography. Morphologically it's not. Phonologically it's not. If you never had to learn to read or write, you'd probably make the case that it's an incredibly simple language^2 (and some people do).

In the past the Chinese government made a concerted effort to simplify and modernize the Chinese language. Has the same thing ever happened in a Western language?

The ways in which various Chinese governments have made these efforts is significant.

The earliest efforts were ultimately those of script reform, to standardise the way various speech communities wrote their words. When you hear the myth^3 of the Qin emperor standardising the written language, this is what's being referred to.

Another important push was under the Nationalist government in Republican China when the Ministry of Education was pushing out dictionaries of STEM terminology. The problem that needed solving was you had multiple people joining the modern scientific world but not having a consistent lexicon on which they could rely. The standardisation was intended to help people be better able to work together.

And of course there's simplification. I feel like this has come up a lot in the last few days on AskHistorians, so sorry if I keep repeating myself on this point. But simplified characters weren't actually created by the state for the most part. They were largely shorthand forms that the average person was already using. What the Nationalists and then the Communists tried to do was make them a de jure standard, and so the simplification of the 1950s was really just the government saying "Okay we'll start teaching these as people actually use them, and hope that helps literacy".

Finally, a commonly referenced organ on Reddit (among those posting links about China) is SARFT, the State Administration of Press, Publication, Radio, Film and Television^4. A lot of times if you're on the default subs and you see a news article posted with headlines like "Chinese government to forbid acronyms" (which actually got posted), that's not actually a national law or anything like that. It's just SARFT, and the average Zhou ignores it. The government can't stop you from calling the NBA "NBA", but SARFT can encourage their newscasters to not say it on state-owned TV. The point is their reach and impact is limited.

Now the question of if this has been done in the West. The answer of course is yes. One well known example is that of Portuguese. The government pushed for substantial spelling reform in 1911 which was meant to simplify orthography. Smaller reforms have continued on through to 1990, with each one attempting to further simplify (i.e., bring in line with pronunciation) spelling.

Even more recently you have the Rechtschreibreform in Germany and neighbouring countries. This was an attempt by the governments of the larger German-speaking region to simplify the orthography.

And of course throughout the rest of the world you see these same efforts as well. In Southeast Asia, Lao is a pretty good example of a language undergoing significant simplification in terms of orthography, when a very similar language, Thai, did not. I've written a little about that here.

Then finally since we're using English here I think it's worth pointing out on significant hinderance to spelling reform: The speakers. English is in the situation where there is no standard, even just in America. There are ideas of what the standard is, but nothing that's clearly codified. There is no American English version of l'Académie française to tell people what's standard. Some things have clearly become entrenched, such as not writing a <u> in <colour> (to which we in part have Noah Webster's dictionaries to thank), but these developed out of stylistic preferences and trends, and not because any sort of Ministry of Education told people how to spell.

The closest thing there is to this would be grade school teachers marking things wrong on spelling tests, and then the self-styled "grammar nazis" (who don't really deal with grammar but whatever) "correcting" people's spelling on the internet. I'd written about this last year in this older thread, which you can take a look at if you're interested in English spelling and grammar nazi's more generally.

Anyway, I hope that sufficiently answers your question. Let me know if you have follow ups.

tl;dr: China isn't at all unique in this regard

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^(1. We can argue about how much of a native speaking community there really is, but you see the same thing elsewhere as well so we can skip that for now)

^(2. Again we can argue about the ultimate truth of that statement, that it's simple if we throw out characters, but again we don't need to do that for the scope of this question. The matter is the perception.)

^(3. It's a myth because he didn't do it. Rather, it was a long process that happened over a period of time before during and after his rule. He gets the credit for it because we like those kinds of stories, but as usual reality is less neat and tidy)

^(4. They've actually changed their name to "State Administration of Press, Publication, Radio, Film and Television of the People's Republic of China" but I'm not gonna start calling it "SAPPRFT". I don't even know how to pronounce that.)