I thought that T&C were generally hammered out between employers (who want as much as possible for their money) and unions (who want as much as possible for their members).
Patently NOT. Ryanair DO NOT DEAL with unions. That is the nub of this discussion!!
(I thought) Regulators define safe limits using the lowest common denominator principle (ie to cover all situations and persons).
You thought wrong. Scientific studies by the likes of NASA are largely ignored by regulators.
Politics is the main decider.
Duty time should be linked to duty and rostering IHMO. If one's roster is all over the place with rest not properly allowed for or time zone changes mean rest is very difficult then duty times below FTL are well in order. However, I would contend that the closer an Ops department gets to offering a stable 5 on 2 off roster with no change between early and late during a duty cycle, the more an operator is likely to think that crew can fly close to FTL.
The IDEAL WORLD scenario again. It sounds so simple in your Utopian dream, but in reality pilots are caught on reserves, rung up on days off, and harrassed into accepting duties which ultimately lead to disruption of your shiny happy scenario - and the creation of institutionalised fatigue in their rostering which is argued as being 'LEGAL'.
Oh, and by the way, I think MoL has done more to harm the image of LCC than anyone else to date. I furthermore think that his method of dealing with staff, customers and pretty much everyone is appalling. Some of FR "so-called" cost saving measures are a) short sighted and b) repugnant. And the Ryanair method of doing business has very little to do with SouthWest Airlines other than looking the same
Yet you remain a fan.
How perverse!