Airlines need volumes of pilots -direct entrants (like 100's a year). The sponsorship system (ie 10 in a go) is old hat (part of a poor operating model- the 'loyalty' argument is paper thin, argued (as mentioned above) by the same turgid Fleet and Training captains that got in that way many moons ago.. hey we'd all do it..).. anyway, I digress..
I think the most rational reason for the periodic sanctioning of these programmes is 'social responsibility'.. big businesses do come under fire for not giving back.. whether it be to their designate charities, local environent or (closer to home) their own staff.. they have to be seen to 'give' when they're doing well (or not suffering too greatly).. its not obvious, but at the end of the day the management accountants will advise to an agenda..
Sponsoring pilots is the lower end of 'giving' as its tax friendly and serves in the airline's own (mild) interest, but it just passes as a 'charity effort'...(this isn't cynicism)
Patience