If it was actually 23mins, and not modifiable, then a myriad of important professions would be completely unviable (e.g. medicine). That is to say, it seems doubtful that the impact of interruptions can be meaningfully summarised in a single figure.

I always assumed that would be an average, meaning it takes 5s for some and 2h for others.

Again, the actual quote is not specific enough, but that would be a very wild and easily dismissed claim.

Or those tasks just got prioritized lower and lower.