Well it is a cute idea to suggest that we are as unconfident about spikes as we are the LFP. But I would like to hear your mechanistic explanation for LFP entrainment. Keep in mind the LFP is roughly +/- 2mV in amplitude (broadband amplitude), and the resting state of the neuron is around -70 mV.

Important to keep in mind that the brain isn't one neuron; small effects amplify across many. Cortical neurons don't spike that often. They spend most of the time teetering on the spiking edge, oscillating and contributing to the electric fields. Like Humpty Dumpty, a small push can tip them over.