You are comparing a task to an industry...
BELIEVE ME... "electrician" covers a LOT more than wiring a house...
SOLAR could never be "easy" understanding solar panel specs should be fairly easy...
Understanding wiring a main breaker panel should be fairly easy.
If you try to understand EVERYTHING about an industry... you are going to be quite inundated.
No race car engineer would say the task is easy...
It ain't the same as building an engine... it is understanding center of gravity, vehicle weight distribution, air pressure, fuel density management, altitude, tire composition, track conditions, clutch mechanism materials and disintegration management, track rule comprehension, speed aerodynamics, downforce, bolt loading and stretch, material fatigue and SOOOOOOOO MANY more factors I assure you, SOLAR comprehension for a residence would be child's play.
I have worked in HVAC for 40 years... I was trained by my grandfather who started in 1946, and my father who took over the company in 84... to say I have experience in HVAC is an understatement... I dont know 20% I'd guess of the ENTIRE field. I learn more every day.
I have always worked with electrical... my skills with it qualified me to add electrical licensing to the company. I have finally gained the full unlimited license after going through special electrical license requirements for hvac fields, bumping that to limited electrical then finally unlimited over the decades...
I could wire a house to code in my sleep... bit there are so many aspects to the code, KNOWING even RESIDENTIAL electrical is mind boggling difficult.
Afci, gfci, grounding, bonding, ocp, fuses, ampacity, derating, conduit, wire fill, wire types, box design, panelboards, I could go on and on about what I do know... but BELIEVE ME, it is ALL difficult outside the basics.
You can understand a part of any industry... you could easily comprehend the needs of say a solar generator, and the specs of charging and using that.
Bump that up to the solar needs of powering completely everything a modern home with a fully loaded 200A panel house? Yeah... there is indeed a lot to learn. And a lot of pitfalls that experience gets you understanding.