Generally a pro-active response requires more effort than just accepting the default or status quo approach.  Reactive reponses generally have an urgency associated with them  and are often more like a band aid.

That is they cover the problem temporarily but do not necessarily resolve it.  A pro-active approach requires planning which in itself adds effort.

Default, going with the flow or reacting do not involve any preparation.  Planning is not effortless, but the results are typically more satisfying.

Effort, duration, results

Spending more time and effort should produce better results.  This applies regardless of the product or service. However there is a caveat, both time and effort must be productive.

The act of just spending time or randomly acting on anything may or might not be effective.  The better approach is for it to be thought out (i.e., planned) for maximum effectiveness.

Pro-actively planning the approach, what, when and how is far more likely to result in successful achievement of the objective.

Repeatable and Sustainable

Another often overlooked benefit of the while thought out action is the ability for yourself and others to repeat it over a long period and expect consistent results.

This is the underlying concept of many activity models like ITIL, CMMI, Cobit or 6 Sigma. These models provide a framework for planning.

Ultimately the pro-active approach produces better quality, time after time.  This concept can be applied to anything you do whether it be a trip to the grocery store or a trip to the moon.