I also change oils about half of the change interval. (exept for race car i changed after every run, but the usage is slightly different)
The "long life" service intervals are for fleet managers / leasing providers who don´t want to have vehicles out from road too often. (these are vehicle manufacturers biggest customers, not invidual consumers) Back in early 2000:s when first long life service interval vehicles hit in the markets there were huge amount of 3 year old vehicles out from lease fleets from XXX brand, driven under 100 000km (60.000miles) where olis have been just changed 3rd time. Cams weared almost round because back then they did not had roller tappets.
Anyhow: By addictives its possible to slow down the detoritiate effect for the plastic parts. It cant be complete avoided. There are hundres of types of plastics and its impossible to cover all of them, so typically manufacturers choose one (or some) partner for co-operation.
Agree: Like i wrote earlier, manufacturers only care that the vehicle last problem free over warranty time / acceptable service life (5-8years) to get customer back.

For these who think oil recommedations are just marketing: If it would be marketing, why not all XXXX manufacturer oils are not recommend for all XXXX engines?
This is not only JLR. Same thing for MB, VAG, Ford... Certain era of engines have recomendation of XXXX speck oil and next gereration engine it can be same brand (or different brand) but different spec. Why? Why bother to make all new sertifications, labels etc, just waisting money for making new oil products if it dosent matter and its just marketing co-operation? (got you thinking now, right?)
Oils recommended for JLR (Ford) engines are not even expensive. Low mid-range oils, so i really don´t see the point why people are ranting about and driving vehicle looking like million buck$. -> Buy Lada.

Again: Your vehicle, your money.
Enjoy your ride.

 

After looking at some of the engine pictures in a lot of the threads/post about oil leaks I fail to see any need for any kind of dye to aid detection!!!!

 

I have read that the dye is not for leak detection but so the JLR dealership can see if the recommended Castrol brew was used or not, in respect to warranty claims.
If my car were still under warranty but I had an engine related claim refused because I used another oil (eg not Castrol) and that oil met spec I would raise a ginormous fuss!

 

Well other than that oil leak dye can be purchased & added to any oil, I guess that could be a sort of related side function.
Could be an Australian dealership thing. Things are definitely done different down under, where dirty deeds are done dirt cheap.

 

Somewhat true, however engine plant is not the same as final assembly. I drove design in both and plants have issues of course with labor. Most of processes are highly automated both in assembly and test. The cost of poor quality exceeds the ability to staff Union labor - Brigend did not have that problem until the later years.

I'm speaking specifically to Ford global processes - I'm not a champion for every product or process, but the decisions to specify oil I do not take lightly. We would get squeezed for cost way too much to add work to a chief or principal engineer for spec approval especially in the 2010s...