Instead, it's become a money pit, costing more annually to maintain than the median price of a Boise-area home. What's more, Idaho's current governor won't even live there.
Public outcry was on display this week at a hearing over the house's future, where a majority of those who spoke recommended either selling the place or returning it to Simplot's family.
But as Idaho has discovered, it's easier to take a mansion than it is to give it back: The heirs to the self-made billionaire who died in 2008 at age 99 don't want it.
"The family's position hasn't changed," said David Cuoio, a Simplot spokesman, on Wednesday, referring to an earlier statement. "J.R.'s home was given to the state with the understanding that it would be used as the governor's house."
The place, along with its 30-by-50-foot American flag, was erected by Simplot back in 1980 not simply as a residence.
Connected to the Boise Valley floor by a narrow serpentine drive, the 7,100-square-foot home is meant to be noticed.
In real estate parlance, location is everything, but that's also the reason the "the mansion on the hill" sticks in the collective craw of many Idaho residents.
"The governor of Idaho should be a person that the citizens can relate to," said Robert Fries, a Boise resident. "The governor of Idaho should not be placed on a pedestal on a hill, looking down on everyone."
Simplot handed over the keys in 2004, but it took just two years for its lofty perch to become an issue in the 2006 race to be governor: The Democratic candidate promised he'd never live in a house that seemed to elevate a politician above the ranks of the common man.
Current chief executive C.L. "Butch" Otter won, but the Republican also eschewed the mansion, preferring his riverside ranch west of Idaho's capital. There's some personal baggage, too: Otter is Simplot's former son-in-law, having divorced his daughter back in 1993.
And then there's the cost.
Just to maintain the 37-acre grounds, the state will pay about $80,000 this year, part of a cost-sharing agreement with the Simplot family that also covers adjacent property it still owns.
The list goes on: Electricity, $30,000; replacement flags: $5,100; janitors to clean up after rare occasions the house is used for state events: $12,000.
Altogether, the maintenance tab through next June is forecast at $177,400 $40,000 north of the median Ada County home.
Consequently, a fund to maintain the mansion has dwindled to just $900,000, from $1.5 million in 2005.
"It seems to me to be a waste of money," said Barbara Kemp, another Boise resident.
The mansion isn't without defenders.
Boise resident Michael Kostanecki thinks Idaho should keep it as a tribute to Simplot, who rose from a modest childhood in Declo to found a corporation that supplied McDonald's with its golden french fries.
"For the life of me, I can't believe we would let this symbol of Idaho go to some developer," Kostanecki pleaded Tuesday with the five-member Governor's Housing Committee.
They find themselves in a tight spot: not offending Simplot's family by looking a gift horse in the mouth, while still staunching the cash drain.
The chairman, Republican state Sen. Chuck Winder, prefers keeping it.
Democratic Sen. Les Bock, another member, favors disposal.
For another month, they'll be taking public comment on what to do, but reaching a conclusion everyone can live with still won't be easy, Bock concedes.
"At least we have some input into what we should consider doing next," he said.