In the federal courts, I think it is more a matter of philosophy than of economic necessity. Unlike state courts, federal courts use the single-judge calendar system, meaning that any given case is assigned to one judge for all purposes from beginning to end. This means that a judge who is proactive in managing cases will reap direct rewards in keeping his docket under control. In addition, federal judges sit for life and cannot be removed except for grounds justifying impeachment. They thus has enormous power and some run their courts almost like little fiefdoms (or at least it seems that way!). When they want to twist arms, the parties have little choice but to comply, even as they might buck and kick in the process. In any case, when high-powered lawyers and their litigant clients come into federal court and try to muscle the court and the other parties, the judge has a basic choice: do I let this go on unchecked or do I set a tone by which I control things. Eventually, the judges realized that they had to be aggressive in setting the right tone and this in time became the norm with many of them. It definitely ties in with the idea of not letting the courts be completely overwhelmed but it is not budget-driven as such but rather is motivated by necessities of reining in cases (and lawyers and parties) that would otherwise run wild to the detriment of the judge and his docket. Today, federal judges will vary on how much they use such power to curtail abuse and to promote aggressive management but the trend is very much, as you say, toward proactive management.