Does Les think God no longer performs any miracles?
No, God is still the God of miracles, can still answer prayer, and can still perform the miraculous. But the specific supernatural interventions Israel experienced—angels opening prison doors and controlled earthquakes—are not happening now and will not until God again deals with Israel.
Les explains he is not saying God isn't the God of miracles. He affirms God can still answer prayer and perform the miraculous, but he distinguishes these from the kind of supernatural interventions Israel experienced, such as angels opening prison doors and earthquakes that released prisoners without killing them. That specific supernatural activity, he says, does not happen now, hasn't happened, and won't until God begins again to deal with the nation of Israel, when it will return as a daily occurrence.