It's not arrogant if it's true, it's just candid.
We would never communicate things like that - that would be arrogant, but if he's giving us the reality, then it's fine.
That said - the 'Red Flag' to me is that someone things they are going to 'contract' and 'help out a bit' and 'fix their architecture'.
This seems worse the a bit glib, it seems upside down.
This seems like someone who might be a good engineer and who has worked on good teams ... but doesn't have the maturity to understand how these projects tend to unfold.
'Fixing a Broken Project' has to be the most scary thing in software and in most cases it's not doable.
Teaching some best practices - yes. Helping to identify problems - yes. Maybe slicing off a few obvious things, sure - i.e. maybe they need a caching strategy.
But when 'Thing are Wrong' there are usually a lot of problems and 99% of the time, someone thinks they can hire a 'Savior' to come in and fix it. The 'Savior', offered a pile of money is likely to buy into their own ability to be the 'Savior'.
But the psychological development from those frothy heights, as the realization sets in that they're crashing on the rock of Scylla ... well there has to be a good German word for that.
We should try to recognize the variety of inputs that may have created what resulted in seemingly an 'architecture problem' when that might not be the source of the conundrum. A team of 'mediocre people' will probably only ever be capable of doing something to a certain calibre. The Winnipeg Symphony will never sound as good as the NY Philharmonic, College Basketball teams are not competitive with Pro Teams etc..