what makes people lose control in complex plane and not fixed gear?
I dont understand the big difference.

As has been discussed at least twice in this thread, it is not that much
that retracts lose contol more often, it is that they're less forgiving when
they do. The fixed-gear pilot has longer to figure out what to do and
speeds stay under control enough that they have a good chance of emerging
from the bottom of the cloud and getting it upright. The retract has either
broken up already, or emerges from the cloud 40K over redline and the pilot
pulls the wings off attempting to recover before hitting the ground.

I'll also note that my Bonanza is much more laterally stable with the gear
down, but I don't really know if fixed-gears tend to be more laterally
stable as a rule.

- Mark