For better or worse, this is not the Massachusetts I grew up in back in the 1970s.

Northeastern University Professor Andrew Sum’s recent study on ballooning income inequality here in the Bay State represented a rare “a-ha moment,” sliding into place a crucial missing puzzle piece.

It’s long been clear the rise of the posh downtown condo tower in the Hub and the pretentious McMansion in the suburbs were simply surface signs of deeper changes in our local and national economy.

Sum’s study fills in a big gap here, spelling out those changes in cold, hard numbers how the rich have not only grown richer – but also more numerous.

Now And Then

Yes, our state has grown much wealthier since the 1970s, but not equally so – with profound implications for the future of real estate in Massachusetts.

Today, Massachusetts is one of the wealthiest states in the country, No. 5 in median household income at $61,133, according to federal statistics.

It is a rise that has been driven by the steady expansion of technology and now biotech industries in Cambridge and Route 128 and Interstate 495, and high-paying financial services jobs in downtown Boston.

We’ve gone from a factory/production economy to a knowledge economy, and our universities and research hospitals – always a plus – have become decided advantages.

That’s a big jump from 1979, when Massachusetts didn’t even make the top 10 wealthiest states, coming in at No. 13 in household income and saddled with an aging manufacturing economy that was bleeding jobs.

But even as overall wealth has grown, the distribution has grown more lopsided.

Massachusetts ranked No. 24 in terms of income inequality back in 1979, according to the Northeastern study. Today we are No. 5, with the top 1 percent raking in more than 24 times what the bottom 10 percent takes home – more than double the 1979 number, according to Sum, director of the Center for Labor Market Studies at Northeastern.

Yes, our state, and especially the Eastern half of it, has changed and changed dramatically over the past 30 years. Childhood memories can be faulty, but when I grew up in Norfolk in the 1970s and early 80s, the Boston suburbs were nice, yet not all that different from suburbs across America.

Built in the late 1960s in what had been a stretch of undeveloped woodland, the neighborhood where I grew up was a nicer but clearly recognizable cousin of the cape, colonial and raised ranch subdivisions to be found from California to New Jersey. Some houses were a bit larger than others, but in essence, they all looked as if they were simply different lines from the same factory.

My Dad worked in management for a manufacturer – it was the kind of secure job people aspired to back then. As for high-tech, that was represented by the Scout master down the street who worked at Raytheon, and the Polaroid guy who everyone thought was a bit eccentric for fiddling around with computers on the weekend.

Failure Of Management

I went away to college in the mid-1980s, just as the Massachusetts economy began to take off. When I returned to the western suburbs to house-hunt back in 2002, the changes I found were nothing short of dramatic. Demand for homes in upscale towns like Weston, Wellesley and Concord had gone nuts, driving up prices in towns like Needham and Medfield that had been solidly middle class.

Modest ranches and capes were now seen as stepping stones or candidates for tear downs, with graceless faux mansions taking their place.

A drive through my old neighborhood told it all, with comfortable 2,000-square-foot colonials built in the 60s suddenly giving way to sprawling, 4,000-square-foot (and up), custom-built homes rolled out beginning in the late 1980s and continuing through the early 2000s.

Yet, all that said, it’s wrong to try and twist this infusion of wealth and jobs – even if it has been far from evenly divided – into a bad thing.

But it has had unintended consequences, especially for the local real estate market.

Despite my trip down memory lane, Massachusetts in the 1970s was fast becoming a rust belt state, saved in the end by the ingenuity of entrepreneurs like the late Ken Olsen, Digital’s founder.

And at least when it comes to real estate, the problem is not the wealth that has been pouring in, but how we’ve failed to manage this new demand.

As wealthier newcomers have turned towns like Weston and Sherborn into elite enclaves, they’ve effectively closed the door behind them.

A mess of restrictions on new home building has led to a steady drop off in new construction over the past quarter century, meaning the few homes that do get built are too often of the McMansion variety – profitable for builders, to be sure, but still relatively unattainable for most “average” buyers.

We have one of the oldest housing stocks in the country, with a big chunk of homes built before 1939 or during the post-war 1950s building boom.

That has left most of us, even those with relatively healthy incomes, battling each other for the right to buy aging homes – and bidding up prices in the process.

The 1970s were no great shakes, but at least when it comes to the ability to buy a home in our fair commonwealth on a middle-income salary, it beats today.