Given their lack of tithing requirement and the fact that they have the lowest educated membership of any denomination surveyed by the Pew Foundation, they have to find a way to monetize their members' labor.
Once upon a time, that was accomplished through field service. Even if members sold one magazine per hour, that was $.25 per man hour the WT was receiving. My guess is the WT hasn't been turning much of a profit on literature placements in a very, very long time.
If they were to turn their volunteer literature-distribution salesforce into a construction force, then they could monetize their labor in the context of a real estate model: construct various buildings using free labor and a few years down the road sell them at market price. It doesn't take a genius to figure it out.
As to the video production piece, I think it has to do more with the GB's ego and information control. Instead of allowing talented orators to become powerful locally, they can pump in the desired message directly to kingdom halls across the world. It also solves the problem of having a real lack of qualified public speakers in some parts of the world. A movement towards pre-packaged video content in lieu of talks presented by local speakers might explain why they're doing away with the theocratic ministry school.