The wealthy did have superior technology: swords, armor, horse gear, and trained horses. These were extremely expensive and could be used effectively only by well-trained elites: knights. This technology was, of course, directly useful for maintaining power.

A major force in the destruction of this power structure was the gun: A simple gun need not be much more complex than a metal tube attached to a piece of wood, and learning to load, point, and fire took relatively little training. This radically devalued the older military technology. In Japan, of course, highly trained samurai kept a grip on power  by suppressing gun technology.

Regarding the view of guns expressed in the diary, one shouldn't regard the use of an effective technology by a power elite as evidence that the best alternative would help equalise power.

Words and ideas I offer here may be used freely and without attribution.