I don't mind the old school style of three cars, however, in the spirit of getting with the times the cost for a third car would push small teams out.
No doubt that's his intention. Luca has been smarting about the new teams since Karun Chandhok inadvertently blocked Fernando Alonso at Montreal last year - Chandhok went right coming out of Turn 6 to let Alonso through, but Alonso also went right to under cut. It was an honest mistake, but it was enough for Jenson Button to slip by. Ever since then Luca and Ferrari have been very critical of the new teams (since the infamous "Horse Whisperer" blog is essentially their way of saying things they cannot be seen to sy in public). Customer cars is one way to do that, because it means any success the new teams experience can be directly attributed to the team they bought the chassis from.
And that's the problem with customer cars: they create an imbalance in power.
Before 2010, there were only ten teams in the sport, and a handful of engine suppliers. The engines were supplied by the manufacturers, so the more customer teams an engine supplier had the more power they got. Ferrari in particular had a lot they led FOTA, and they supplied two established teams. Mercedes asupplied three, but one of those was Brawn. Renault and Toyota supplied two, while BMW only supplied the one. All of the manufacturers were close.
But then the three new teams arrived in 2010, and they all used Cosworth power. And while Ferrari picked up Sauber as a customer team, both Toyota and BMW withdrew, Renault scaled back their involvement, and Mercedes split with McLaren to focus on their own team. The net result was that Ferrari lost a lot of political power. Where they could use their influence to command half the grid in 2009, they could control, at best, just one-quarter of it in 2010. Ever since then, they have been lobbying to gain more control through customer teams.
The problem with customer cars is that it will give them even more control over the grid. With Cosworth and Renault being external suppliers, the manufacturer power base is thinned out, and the power-sharing between the manufacturers was what kept one of them from getting too much power before 2010. That is now gone, so Ferrari will have an unprecedented amount of power they could command up to half of the grid, because the success of customer teams would be attributed to Ferrari, and they could use that to their advantage. And with the accusations that Red Bull overspent according to the RRA (which could have them stripped of voting powers in FOTA), they would have an almost unlimited ability to control the future of the sport, and they will invariably control it in a way that is good them first and everyone else a distant second.
Thats what Ferrari really wants power.