In my understanding the treaty simply did not reflect the actual longterm power balance after the war, aka, the entry of the USA had shifted the situation in favour of the entente to the point where they could temporarily enforce a much harsher treaty that was not really rooted in the actual battlefield strength of France & the UK and when the USA eventually withdrew they were simply not able to reinforce their position accordingly, resulting in the enormous revanchism in Germany being able to flourish.

Basically: the treaty was too harsh but not in terms of its content but because it was fundamentally based on a participant who, for many years, had essentially only wanted to passively profit from the war economically and had practically no serious political goals when it finally entered into it aside from securing its returns which were not a result of targeted funding but the entente dominance at sea limiting the ability of the central powers to engage in trade across the Atlantic.

I know this second part is unpopular but I think that it holds up well when we look the political developments at the time.

TLDR: the central powers were not as weak as the treaty which was enforced with the help of the USA, which resulted in the collapse of the power war system when the latter left the picture again.

PS: a harsher treaty was not possible because the USA understood that if it wanted to dismantle Germany, this would have likely lead to the former being the one who would have to ultimately become involved in an unprofitable longterm commitment to secure half of Europe against Soviet communism, which granted, is quite ironic due to the later developments, not to mention that it’s anti colonial legacy meant that it as not willing to give the remaining European colonial empires all they wanted on the continent.

I would draw a link to what happend to France after the Napoleonic wars - the US-American goal was to establish a balanced Europe, mirroring the actions of great powers roughly a century prior.