Unlike solar and wind (inverter-based) generation that must be changed into matching waveform as conventional generation, the coal-fired plants require large number of employees to keep plant operational, including welders, bulldozer operators, trainloads of coal etc.
Offsetting job losses as more renewables come on-line is the need for grid reliability ... specifically to keep voltage "within ±10% of nominal at all points across the grid." Keep in mind the grid is cris-crossed over millions of square miles, with millions of poles and transformers and customers ... comprising a system that might not be fully mapped at the distribution level in 2021. Read

Utility-size generation from renewables has a large footprint (as does oil and gas) that hinges on large-scale land acquisition usually located far from end users ... which requires further land access to build transmission lines to urban centers. Read.  The less reliable renewables come with a "reduction in fault currents and short circuit strength" ... meaning that "voltage support is a vital ancillary service to prevent voltage instability and ensure good power transfer." Renewables require gas-fired generators that sit idle but come online fast when needed (viewed as uneconomical or impractical?) .... but also require retrofitting the grid with capacitor banks, and voltage regulators etc ... and possible future innovations such as transformer tap changers, massive batteries and solid state transformers etc read  read2 read3 read4 read5 Resource: Electrification magazine

Utilities are challenged by aging networks ... challenged by economic growth ... challenged by changing resource mix from solar and wind ...  but also challenged by electric vehicles that will try to replace the entire gasoline resource with electric resource. Read Read Read
The future will need .... new skills from labor ... innovation using electronics that are more vulnerable to lightning and solar storms ... changing standards to meet reliability goals ... protecting appliances with voltage monitors that shut off appliance if voltage drops ... all indicating that considerable costs will be passed onto customers ... and arguably 25% of the energy will be used to manufacture, retrofit and maintain changes.