There is something to be said for the financial situation of these owners.
John Henry has a net worth of $2.6 billion (per Forbes). While he (and other owners) do not use their own cash, Henry clearly has shown he has no issues keeping the Sox at or near the top of the MLB payroll hierarchy. The Greater Boston Area is the 10th largest metropolitan area in the US per the 2010 census, which certainly helps.
Oakland A's majority owner John Fisher has a net worth of $2.8 billion (per Forbes). The A's play in the 12 largest metropolitan area. Now they do share it with the Giants, which is a big deal. But does this impact them to the point where they have to operate among the lowest payrolls in MLB? I can see the issue here somewhat, as it would be like if Boston had two MLB franchises. Can Boston support two MLB teams? It only seems to work in the 3 largest markets (NY, LA, Chicago). If Philadelphia-DC-Baltimore was considered one metropolitan area and not 3 separate ones, it would be the second largest market in the USA, ahead of LA and behind only New York. (Again, all data per the 2010 census.)
Miami Marlins majority owner Bruce Sherman does "only" have a net worth of $500 million (per Forbes), but the Marlins do play in the 7th largest market in the USA per the 2010 census. But a lot of other money does come from his rather wealthy partnership group that includes Derek Jeter (Forbes net worth - $200 million) and Michael Jordan (Forbes net worth - $1.6 billion). So why do the Marlins frequently cry poverty? They have the population and the money upfront to put a team together. On the surface, this team appears to have the worst excuses for crying poverty and small market. It's not a small market.
Pittsburgh Pirates majority owner Robert Nutting has a net worth of $1.6 billion per Forbes, which dstill makes him one of the 10 richest owners in MLB. Now they do play in the 27th largest market in the USA, which certainly has an impact. But at what point is he just refusing to invest in his team to put a better product on the field and take advantage of what is still a rather large and robust market? I get it is easier to support NFL teams (with a lot fewer home games) and NHL teams (significantly lower budgets).
Tampa Rays owner Stuart Sternberg has a Forbes net worth of $800 million, and the Tampa market ranks 18th largest in the USA. Wht I think kills this team is 1) the inconvenient stadium and 2) the Tampa market is flooded with retirees mostly from other states who brought with them their own team allegiances. It's a large market, but I am not sure how accessible it is to the Rays, who really need to relocate at some point. If there is a market that could support a second team, the Dallas-Forth Worth-Arlington market is probably the best option. Personally, I think New York City could support a third team, like they did for a long time. Bring back the Brooklyn Superbas!!