A lot of people do recreational drugs while at college and go on just fine. George W. Bush, for example, is alleged to have taken cocaine.
Snorting will also shoot your tolerance through the roof, so taking it orally will no longer be as effective. Definitely not a road I recommend going down
And basically any big name in the financial industry has almost certainly used loads of cocaine. They’re mostly not suffering any horrible consequences.
But of course there’s a world of difference between cocaine use and addiction. An addict might start their day with a line, every day, but that’s far from typical use.
When a pill is swallowed it is gradually released into the bloodstream. Some drugs are also partially degraded by the digestive system, meaning you don't get 100% into the bloodstream. For some drugs, as much as 90% or more can be destroyed in the stomach, but this is accounted for in the dosing. Your stomach contents also go through your liver, which does first-pass metabolism depending on the drug and can reduce overall concentrations.
When someone snorts a drug, it bypasses all of that. It has easy access to the brain. It spikes the concentration the brain sees far in excess of what you would get from taking the drug orally.
This spike is where the damage is amplified. A sudden spike to very high values can overwhelm the brain's protection systems, for example.
Dopamine degradation produces neurotoxic metabolites. The brain is normally decent at cleaning these up, but when you consume drugs that spill that dopamine out at excess rates and disrupt its storage in vesicles then you can also overwhelm the brain's ability to clean up safely.
The sudden spike also causes rapid downregulation of the affected receptors, leading to deeper withdrawal effects that can last for a long time.
The sudden spike is also more euphoric. Combine that with the deeper withdrawal and it's why taking a pill through the nose is far more addictive than taking it orally.