Small reactors are not expected to be any cheaper than traditional reactors. They are a better bet right now because the traditional reactors keep getting mothballed in developed nations, and they have some clever technical innovations, but these are not complete game changers.
Each decade, nuclear builds also trend towards getting more expensive. Like it or not, it at least partially Fukushima Daiichi that killed the nuclear expansion US. The AP1000 had new missile shield requirements that was slowing it down before that happened, and then the Japan accident added even more regulation. There was an anti-nuclear chair of the regulatory commission at the time, and yes, this is fundamentally political, but it's hard to push back on these specifics.