You might be confusing Book Value of a business with it's value as an asset, and how returns are measured. "return on actual businesses" is impossible to measure with any precision.The time horizon chosen for returns on securities is usually short. So, the returns on securities will almost always seem too high or too low compared to what is happening in the underlying business.
The market returns are calculated over a fixed and usually short time period and are easy to calculate. Because the markets in question are expectations markets the prices move around a lot and hence the measured returns move around a lot.
Compare that with defining "returns on actual businesses" in a way which is both sensible (ie accurate) and has even a reasonable level of precision - it's impossible. For example, a commonly used and easy way to measure it is Return on Equity. Net Income / Book Value. Book Value is an accounting number based on the past. The "true" value put on an asset by investors is based on guesses about the future of the business and said business's ability to put cash in the pockets of the owners. Net Income misses important value changes - consider Intel, who have been making crazy decisions for years which allowed AMD back in the x86 server game. Intel don't have to report a "we did stupid things which will cost us billions in 10 years time" on their income statement for a given year. So, RoE isn't good and other similar numbers are similarly bad.
So, your statement about returns on securities should really say: "for the last few years, returns on securities appear to have exceeded the changes in value for the underlying businesses". To which a reasonable response is: "Yup, it happens sometimes".