When I studied coding >20 years ago we learned coding 'to the metal with assembler, C and so on, including multithreading. Back then we studied pure programming, we didn't have stuff like Unreal Engine or Unity and the universities or schools didn't teach -at least here in Spain- gamedev specific stuff. The hardware had insane limitations so the code had to be super optimized.
Today students learn mostly UE, Unity and related stuff. They don't have to make most of their own engines, drivers, tools or libraries because someone else already did it and is available. The hardware is super powerful so the optimization required is almost nothing compared to when a game had to be fit in 64KB (or less in some cases). So the younger coders typically are way worse at optimizing and specially everything related to low level stuff than the senior coders.
And well, they are way less experienced, skilled and have way less knowledge in general. But they have more passion, energy and willing to crunch. And have the senior and lead devs to mentor, teach and guide them.