I think it does need to be noted that Saudi Arabia has a very large number of fields that have never been tapped - not huge ones by their standards, but certainly big enough to delight everyone if they were suddenly found in the North Sea or the GOM. They could probably increase production if they were to make a herculean effort to develop those fields (eg hundreds of rigs rather than tens). This would be at the price of greatly shortening the ultimate life of their production for the sake of a higher peak. All the noises they are making suggest they have no intent of doing any such thing (and why should they, from their point of view).

I think we probably want to be a little more cautious in extrapolating the Texas example. For example, Samotlor went into decline in 1980, but West Siberia as a whole didn't peak until 1988-89 (because they brought on a slew of other fields).

It is these considerations from the bottom-up that suggest to me that the Hubbert linearization predicted slow declines might be plausible - there's a lot of oil in both Saudia Arabia and Russia that is being held back just because it's owners aren't in a great rush to develop it. Probably a good thing for everyone in the long run.