I don't see why we need this so called baseline. It is an outdated concept pushed by the nuclear industry. We need (i) to harness the cheap energy coming from the sun and the wind and (ii) another source of energy to make up shortages when solar and wind are unavailable.
The source (ii) should be able to be ramped up and shut down quickly, which is a requirement where nuclear flat out fails.
The baseline concept of a power source that is steady and cannot be quickly shut down or ramped up (i.e., nuclear or coal) really does not make sense in a world where you have access to very cheap but somewhat unpredictable sources of energy.
Ideally, source (ii) would be electricity storage. This is not available now at the necessary scale (but it is getting closer and closer to reality). So the other alternatives are hydro (ideal if available in your environment, but not always available) and gas.
Nuclear doesn't enter into it. Starting up and stopping nuclear reactors is a difficult time consuming process that cannot be done on demand.
And yes Gas is falling on its face right now, but that is not due to any fundamental limitations of gas. It is because a lot of the US nat gas is mined and transported in Texas and the Texans did not winterize their equipment.
I expect renewables will keep increasing in combination with gas, until power storage becomes available.