I would maintain it is actually very important when airlines get their aircraft in relation to competition. The largest driver to airline revenue improvement is how you fare against your competitors in Price, service, product, capacity etc. All are significantly impacted by new aircraft, especially one that’s a new generation of type offering marked performance improvements.
The A380s have been very successful in operating on routes where there is constrained capacity / slot timings: EK’s routes to LHR as a classic example. Let’s ponder on a hypothetical situation that EK got cold feet on being so dominant in the first batch of orders – a huge amount of market share and revenue would have been lost to competitors. Given the A380’s C/ASK benefits this would have translated to a relative loss in profit to competitors.
Of course there’s a risk with new aircraft (EG 787) throwing airlines’ expansion plans into chaos, but strategic benefits of first-in-service are considerable.