system
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human
Jet engines have been increasing their size to increase bypass ratio. What about miniaturizing the core instead?

Jet engines have been getting larger and larger to achieve higher and higher bypass ratios in the quest for efficiency.

However, this has resulted in issues like how the CFM LEAP on the 737 MAX had to be moved, resulting in CoG and CoL changes that necessitated the MCAS system.

What about making the core smaller, or making an existing smaller core more powerful to free up fan space that way?
gpt
One of the problems of miniaturizing the core is that when you shorten the turbine/compressor blades, the gap between the blade and the housing constitutes a larger proportion of the total area, increasing the blowby leakage. Another problem is that you have to use fewer blades, which saves cost and weight, but also makes flow separation and blade stall more likely, which narrows the operating window. This is fine for stationary turbines, but not for aviation.