John,
All the examples in the training paper had a common factor, the maintenance was interrupted, carried out in a hurry or stages were skipped in order to get the plane out on time. The root of nearly all commercial aviation accidents is money. Commercial pressures to keep aircraft available, pilots abbreviating pre flight checks to get in the air on time, overloading or incorrect weight and balance checks before a hurried departure. Training programmes have been cut back or compressed and maintenance directives deferred for as long as possible in order to maximise profits for the airline and its' shareholders.
Airbus arrived at their cockit design through wanting to save as much weight as possible. Less weight in the aircraft fixtures and fittings means more passenger and cargo revenue and lower fuel costs. Side stick controls meant the cockpit could be made smaller allowing a bit more room for the passenger cabin and an extra row of seats. Not a bad thing in itself, but it can have a negative effect on ergonomics, as has been theorised in this thread.
Maximising the return on investment is all that matters to airlines these days, aircraft and crew are just resources to be used to the fullest extent possible without actually losing an aircraft through fatigue, crew or mechanical. You can be sure that the company analysts at all of the big airlines have factored in the acceptability of losing an aircraft or two against profits and insurance costs.
I recall reading about the existance of a confidential memo many years ago which indicated that paying for the loss of three aircraft during their operational life would be cheaper than delaying further production for modifications and doing a recall to fix a design fault that had been discovered. This mentality is by no means confined to the aircraft industry. Every day products are released to market with known deficiencies. The manufacturers find it more profitable to just replace faulty goods rather than redesign the product.
Even when human lives are at stake, it often takes an extraordinary amount of campaigning to to get the fault fixed. How many vehicle manufacturers have maintained that their products were perfectly safe before issuing a recall notice to all owners? It all comes down to money.