Maduro's appointed generals in charge of sections of the civilian government. He's made them in charge of large businesses, with all the power and money that comes with that. To a large extent he's militarized the economy and civilian government by increasing what the military controls.

At the same time he's arrested those suspected of being subversive or insufficiently loyal, holding them without trial or with what amounts to mock trials.

What rank-and-file soldiers do may be different, but when they've stepped out of line they've seen those who betrayed the fatherland dealt with brutally and quickly. In those situations, unless you knew that you had a sufficient organization and numbers to win, if you're not at the top you're going to march in step. Plus in an economy that's run for the government by the government, the best place to be is working for the government.