Was this an intuitive development?

Essentially, yes.

"Base load power" wasn't some conscious choice on the part of any engineers, it's a term that developed to quantify a behavior in power systems- namely, that some devices (such as refrigerators) and industries (steelmaking, radio and television broadcasting; anything with continuous-flow manufacturing) will use electrical power at all times of day, while other devices (televisions, coffee makers) and industries (anything with batch manufacturing) will use power only at certain times of day.

With most systems, modern and not, it is often difficult to "make hay while the sun shines." (Indeed, rain and clouds preventing haymaking was a cause of food shortages!) People need electricity- or mechanical energy, as in the case of the mechanical devices that predated electrical, relying either on steam power or hydromechanical- when they need it, the energy simply not being available prevents that source's adoption, and making it available on demand is worth a lot of effort.

If you didn't have electricity half the year (even if you had three times as much as you need the rest) and you neither knew nor partially controlled when it would be available, would you use a clothes washer, a refrigerator and an electric stove, or a hand washer, an icebox and a propane stove?

Burning coal to generate steam was reliable; hence, it was adopted. 'Dispatchable' power plants are also usually fossil-based, formerly using diesel and often using natural gas today. These are often less efficient than base-load stations (as an extreme example, CHP gas base-load stations can have an energy efficiency in excess of 70%, while dispatchable gas turbines have an efficiency of ~30-35%); however, power grids require very close matches between supply and demand, and failures here can literally destroy both production and receiving equipment.

Solar PV and wind are 'intermittent;' this is different from dispatchable because operators generally cannot control how often they're used. Because of this, you either need to overbuild nameplate capacity and lots of storage or you effectively need an entire spare power system (which is effectively what Germany has.) Therefore, PV and wind are essentially mechanisms for saving on the cost of fuel, and then only where they're reliable (such as sunny California or windy Texas).

A moment should also be taken to consider other renewables; geothermal is base-load; biomass can be either base-load or dispatchable, depending on the type of biomass and how its used; hydropower is both base-load and dispatchable, which is why it's so popular and why it has been so popular since large-scale electrical systems were invented.

So, why weren't wind and solar adopted earlier, even in this capacity? (PV cells have existed since the early 1900s). Well, electric windmills were available in the Great Plains of the US, but both those and PV cells were very inefficient in addition to being intermittent. Wind turbines could have been more developed- but to what point? Fossil fuels, in greater quantities than today, would have been needed to build them, and then they couldn't be as large or tall as today. Even if people considered adding CO2 to the air to be a problem- and IIRC it wasn't clear that we were affecting it until the 70s, and it wasn't clear that this was a problem until the 90s- then those technologies simply wouldn't save much.

Do not underestimate how much all renewables have developed even in the past 10 years.

So why aren't they being more deployed today? Well, they are, first off- production is effectively running flat-out where supply chain issues aren't getting in the way, and improved energy storage in many forms are beginning to make their way to market. Why it isn't going further, it's largely because it isn't clear that renewables can even replace our current system. Two major arguments exist

• all renewables rely on specific valuable and vital materials in order to function, and the amounts needed for a renewable economy sometimes meet or exceed the total resources that exist on Earth.
• renewables-plus-storage almost always have a poor energy return on investment (EROI) and it may exist in too poor a quality for certain applications. In short, you need to use energy to get more energy, whether it's digesting a burger, growing wheat or drilling for oil. Fossil fuels have historically gained 50+ units of energy for each 1 invested (today the estimate is ~20:1); it's very difficult to measure this for PV and wind, even without batteries, but you may get as few as three units of energy for every one invested. (Other reports are far higher, and these discrepancies are nothing compared with nuclear.) Worse, some steps in their production process are not currently possible, and may be far more difficult and energy-intensive, without fossil fuels. Since society relies on the surplus energy, the price of setting it up may be too high for the global economy to bear.

Simon Michaux of the Finnish Geological Survey has done a series of extensive studies on energy and mineral issues, available here. Assessment of the Extra Capacity Required of Alternative Energy Electrical Power Systems to Completely Replace Fossil Fuels is especially good and does include some of the history questions you're looking for; just be warned that it's a large file and that it's conservative in its assumptions. (If you're curious, his recommendation there was to add nuclear.) r/energy and r/RenewableEnergy and r/RenewableTech would also be good places to crosspost this.