Baby brained take from me almost being finished reading Lenin's, What is to be Done....

The workers first priority, in general is going to be figuring out how to get better working conditions. So there's a pretty high chance that any organized group or workers are going to find themselves very active around fighting for local economic gains in their particular location but much less active around trying to figure out how get into the political side of things (that has the revolutionary potential to change the entire employee/employer relationship for everybody instead of just a particular shop). Lenin's not saying that 100% of a spontaneous worker organized movement is going to refuse to involve itself politically but that most workers have more experience with the local economic relations between themselves and their employers and without some outside group laying the groundwork of education and agitation beforehand, the mass worker movement is inclined to follow the path of least resistance and stick to employee/employer relations and avoid getting involved in political change.

Assuming that the organized workers will just spontaneously jump into revolutionary politics after winning concessions with their employers is seen as being a huge risk and very lazy for a revolutionary socialist or communist to just sit back, wait for the workers to "figure it out for themselves" and then take credit for any gains that a mass movement of workers might stumble upon. Lenin critiques this idea and labels it "tail-ism." He argues that the there's a huge amount of potential and momentum but that the professional revolutionary should already have been learning theory, paying attention to politics, developing ways of organizing and communicating that are harder for the State to destroy or intercept to help direct that mass movement of workers towards projects that can have a much greater impact for all the workers all at once instead of piecemeal, factory by factory, shop by shop.

I visualize it like a huge trough of water. I can tip that trough to the side and that huge mass of water will come rushing out but the force is expended inefficiently, too fast, un directed, and leaving nothing for later. I put a spigot on the trough and attach a hose to that spigot, the water can be directed in a more efficient and direct way.

So if Trots are saying, "the workers are the drivers of a revolution", but what they are actually saying is, "the workers will just spontaneously figure things out for themselves", anybody who read Lenin or later theoreticians who agree with Lenin's general guidelines and those who've learned the history of some workers movements that never expanded their revolution into the realm of politics, are going to view Trots as being ineffective, backwards, primitive.