Nuclear professional here. It is true that economics for electricity-only plants have historically struggled to compete with conventional sources, actually below closer to 800 MWe.
The Small Modular Reactor hypothesis is that economies of mass production could conceptually be built that overpower economies of scale. The small reactors of the past, including the ML-1 truck-mounted military microreactor were 10x too expensive even for the military in remote areas. Just building a few small reactors is a losing proposition. If you can get them to "go viral" before they've achieved economic parity, then there's a chance. That will only happen if you successfully market their 24/7 very-low-carbon, very-low land, very-low raw material footprints.
I think for climage change purposes, we should focus on getting costs down on 500-1000 MWe plants. If it takes another round of small prototype non-LWR reactors to get there, then so be it. But large stations are what will displace most of the 84% of the world's energy that is fossil fueled.
Regarding the competition, low-cost fracked natural gas has been deadly to nuclear. I don't think most people realize that fracked natural gas, while great in the deadly air pollution department, is just as bad as coal in the climate change department (when you factor in the methane leaks from wells and pipelines). So if markets can price carbon emissions, natural gas can be ruled out. If not, natural gas will continue to drive nuclear plants to closure and then replace them.
Extremely cheap renewables are a friendly competition to nuclear in that if they're successful, the goals of the nuclear proponents are met: clean, plentiful, cheap energy 24/7. At the moment, the major issues of land use, raw material use, and intermittency are not causing much trouble for renewables. But as they scale up they may encounter more difficulties. All energy sources experience new troubles and regulations as they scale. Coal got scrubbers and filters (doubling+ capital costs), nuclear got the NRC, solar in California recently ran into NIMBY in San Bernardino county desert. Will that continue to get worse? Or are the positive attributes of renewables so good that people will continue to embrace at scale? I honestly don't know. I keep working on nuclear because it's a good high-density resource.
TL;DR: Include carbon-free as valuable in markets and nuclear would do great.