I did a cursory one based on MLB teams when I first read the post. There's just too much of a difference involved for market in baseball so I didn't go too much further since I didn't want to write three paragraphs over something I don't really care about.
Reinsdorf's initial Chicago White Sox investment has gone up in value 80x since the early 80s. Detroit sold for four times as much as the White Sox a decade after Reinsdorf's purchase. I don't know if Detroit started going into the tank by the early 90s, so I didn't know if that was a strong market situation or not.
Without looking too much more, I'm very confident in saying that the odds of finding someone that purchased an NFL/MLB/NBA/NHL over the past 50 years, held it for a decade or more prior to selling, and lost money are very slim. Even if you include year to year operational losses.
Detroit's a bit counterintuitive. The city underwent significant urban decay over a span of decades (starting around 1950 IIRC), although it seemed like only in the 2000s with urban explorers and internet pics of around Detroit and inside book depositories, old grand train stations, etc, did everyone outside the area see the staggering level of decay. Population crashed. At 2010 census, it was around what it was in 1915. Despite all of that, the metro area has thrived. It's held its position as a media market (indicating the people are going from city to suburbs or those who leave the metro are exceeded by those who are arriving in the suburbs), its core industry is still fairly strong (Ford, GM, Chrysler).
Tigers got Comerica Park in 2000, Lions Ford Field in 2002, Red Wings Little Caesars Arena in 2017. The Pistons went to the Palace of Auburn Hills in 1988, the Lions went to the Pontiac Silverdome in 1975, both now in the city again. There was a partial exodus for a while, leaving just the Red Wings & Tigers in the city, but now all 4 teams are back in the city proper. Point is, even among all the decay, the Tigers & Lions still saw the city as feasible to remain in around the turn of the century.
So, the metro area still had a lot of money & economy in it despite the core city crumbling away (and being the epicenter for the ash-destroying bug from China) and the city was still feasible for some teams to remain in or relocate back into from the suburbs.