>No atmosphere, no blowing.    - Tom

I'd answer this somewhat differently.  The rocket jet would indeed dislodge the dust:  The particles

would acquire velocities, and would follow mostly-parabolic paths and eventually collide with and stay

on the surface again. While this might be labelled a "cloud", unlike in Earth's atmosphere these particles

 will presumably return to the Moon's surface in a few seconds, yet far away from the lunar lander.

 As to "why was thick dust still on the ground", most likely the dust was very thick.  

(many meters).

From:   http://curator.jsc.nasa.gov/lunar/letss/regolith.pdf

"The lunar surface is covered by a layer of unconsolidated debris called the lunar regolith (fig. 53). The thickness of the regolith varies from about 5 m on mare surfaces to about 10 m on highland surfaces. The bulk of the regolith is a fine gray soil with a density of about 1.5 g/cm3 , but the regolith also includes breccia and rock fragments from the local bedrock (reviews by Heiken et al. 1974 and Papike et al. 1982). About half the weight of a lunar soil is less than 60 to 80 microns in size. The grain size distribution is given in figure 55."

There may be an additional factor.  As I vaguely recall, there is an odd electrostatic attraction

 between the particles of lunar soil.  Perhaps not surprising, because except for subsurface

frozen-water deposits (and some polar craters) the moon is 'dry as a bone'.