racing oils are engineered to be as light and thin as possible for the application, so they have the least amount of drag on internal components. Also, a synthetic race oil will have a very limited amount of different oil molecules. The molecules are created synthetically in a lab, so the ability to precisely engineer the 'soup' to a specific ratio is possible. Given racing oils light and thin requirement, these molecules will be fragile and have a short life span. The oil will basically be a very limited set of oil molecules, that fit within a very narrow specification. Light & thin oil molecules will break down very quickly, and it's a bit of an exponential curve how fast this happens. When 100% of the oil is fresh and new, the impact between the metal surfaces (say, con rod and crank for example) is shared by 100% of the oil molecules that are being hammered in that gap. The thin layter of oil being crushed over that surface area is all sharing the beating a detonation event or change of piston direction exerts on it.
However, as the mix breaks down... let's say 5% of the racing oil molecules have sheared; the 95% un-sheared molecules in that gap are now seeing 107% of the force. So, they break down 107% faster. Now we have 10% of the oil not shouldering it's weight, leaving 90% of the molecules to take the beating. Those molecules are now degrading at 115% the rate they were when fresh. By the time 80% of your oil has broken down, the remaining 80% is seeing 120% of the force, so the rate of shear is somewhere around 150% faster. By the time you hit 50% sheared molecules your oil is degrading at something like 400% the rate it did when it was new. 50% of the molecules between those metal surfaces are doing all the work.
Race oils are designed to supply you with the thinnest, lightest, most fragile oil molecules that do the job of protecting your engine for a race duration. That's it. Also, race oil does not have stabilizers designed to resist water vapor contamination, which street oil does. Our engines 'breathe' every time they are heat-cycled; they heat up, and the gasses inside the crank case expand. When our engines cool down, they draw in humid air containing water etc into the crank, and that water condenses. That humid air introduces water to the oil, which degrades the oil over time.
This is why, if you store a motor for 2 years, the oil should be dumped because the day/night cycle has 'breathed' 720 cycles of air in & out of the engine, and the small amounts of water in each 'breath' will change the chemical composition of the oil slightly. Also light hydrocarbons will have been 'breathed' off the oil, changing it's weight slightly.
Street oils however, have a totally different engineering design brief. They are a blend of hundreds of different hydrocarbon molecules; there are some small light molecules to provide penetration and high low temp viscosity, and there will be medium & heavy grade molecules designed to last a long time before they break down from shear. It's not as important to have the lightest, thinnest oil molecules possible - it's important to have thicker, heavier molecules that will take street-level stresses for a very long time. Preventing the last 0.01% of rotational inertia loss from your engine is not as important as having an oil which will keep your metal surfaces apart for 20,000 k's. A street motor should last for 100,000 km, and not just a few races.
Using a race oil may feel like it is 'lubricating' your engine better, making the metal bits more 'slippery', but in actual fact you're probably noticing the slight decrease in rotational intertia loss due to a thin light oil. The race oil isn't 'protecting' your engine better, it's just lighter and thinner.
For Street use, if you change your race oil every 3,000mi, and every 3-4 months, there won't be any problems. You're not stressing the shit out of it like when you're racing, and it's low enough miles and time interval that it hasn't degraded enough yet. The one thing to consider is, race oils won't have additives to resist water contamination and degradation, so you DO need to change them regularly even if you don't do many miles. I mean, resisting water contamination is not even an engineering consideration for a racing application - there's absolutely no point engineering for a scenario that should never, ever happen to a race motor.