The recent 'Stolen Thoughts'[1] paper shows many excerpts of private reasoning for frontier models.

For a complex maths problem, Sol reasoned in 367 tokens before working:

  We need solve. Need interpret no person sits next to two other people = among binary string length16 weight8, no occupied chair whose both neighbors occupied, equivalently ab 111 substring. Endpoints cannot have two neighbors anyway; only avoid 111. Count binary strings length16 weight8 avoiding 111. Need N mod1000. Compute stepwise perhaps runs of 1 length max2. Count via runs.
  
  [... cut in half for HN readability ... ]

  Check interpretation potentially "no person sits next to two other people": no seated person's chair adjacent to two occupied chairs. Exactly no three consecutive chairs selected. yes.
  
  Need reason step by step final boxed 907. Explain runs. Ensure people each select chair distinct subset (given subset count). Let's present.

That doesn't look like an overthinker to me, and matches my experiences. There's plenty of papers and research on reducing thinking verbosity/length while keeping as much quality as possible.

I think one of the bigger problems is that verbose, `max`-style thinking does generally lead to higher benchmark scores. And model vendors are incentivised to for benchmarks (at least to some extent).

[1] https://stolen-thoughts.com/