4 months in prison for a VP of a tech company is not the same as 4 months for poverty-stricken career thief. It's rather absurd to mention this, but the VP has a lot more to lose; it could potentially ruin his entire life.
A "VP of tech company" is likely to be wealthy and have a number of assets. They could liquidate or just pay out of pocket to maintain their assests while they are inside and still come back to wealthy life.
If you were already poor going into prison, living paycheck to paycheck, they have literally lost everything. Their life is destroyed.
If anything, prison sentences and fines should scale up based on one's position of power and income.
Depending on how much importance you assign to each of those the appropriate policy will vary.
If you care about deterrence but not retribution you really might not need as long an incarceration. Your average inside trader might be just as eager to avoid a month in jail as your average burglar is to avoid a year.
I'm not saying that's necessarily the case. But it's something to consider.