MSc in Space Technology and Engineering, so while I don't own a single spanner I have a very extensive knowledge of filters, lubricants, and particularly fuels, so I do know about things like lifetime fills.
With modern machining tolerances etc, 20k mile oil intervals is perfectly fine if the use to which the vehicle being put is appropriate (ie, not constant stop start urban motirng , for example), and a suitable type of oil is being used.
Extended intervals are quite normal, even among the budget manufacturers. The average lifespan of an ICE car in the UK has remained pretty much static over the last 20 years so there has been no widespread adverse technical consequence as a result of this trend.
If you want to change your oil or consumables more often than VW advise then all power to you. Nevertheless, unless your vehicle is on an arduous duty cycle it won't bring any tangible benefit, but if it brings you peace of mind then it's worth it to you.
But I stand by my previous post. People moaned about garages taking the Michael with service intervals being too short when comoared to A N Other brand, and parts being replaced when they felt not actually necessary. Yet when manufacturers address this and extend intervals and consumables lifespan they still complain. You can guarantee not a single one of those complaining either way could explain kinematic viscosity or tell you what piston precession is, yet they feel themselves more qualified than the vehicle manufactuer to opine what was or wasn't a technically appropriate and commercially viable service regime.