In my opinion Alonso's Spain lap is the exception to the rule, so i wouldn't use a single data point as basis for my approach to this.
My position however is not related to cost saving, simply to the fact that as I stated earlier on, given the RB/Vettel qualy dominance no matter what you do with the format, it will always be boring, so it's up to the other ones to catch up. I think their ability to switch the tyres on for one lap is part of why they qualy so good, so giving them even more freedom in that aspect should in my view extend their advantage.