…..several cities have seen their teams move out of their city for various different types of economic reasons.
It is a sad reality.

A city should understandably expect a business as profitable as an NFL team to pay taxes.
An NFL team should understandably not want to be taxed at an egregious rate - especially when cheaper options are available.
Both the city and the team have to weigh the overall impact of parting ways as it could be detrimental to either or both.

In my view, the city of Chicago has a lot more to lose than the Bears organization.

In the worst possible scenario for the Bears organization - where all of their fans abandoned the team because of the move out of Chicago - the owners could simply pick from a long list of city suitors and rebrand themselves their with much less taxes (if any) and a stadium that they provide the team.
That is because the franchise brings in enough money, publicity, tourism, and prestige to make the franchise appealing even with the city giving the franchise all of these things.
Chicago obviously does not feel that it can make such a concession.

It is a very hard reality for proud people in a great, great city like Chicago to accept, but their financial situation no longer allows them to hang on to their NFL franchise without a charitable owner regardless of their size. If they can't offer what others can, and if what the city is asking exceeds the costs of moving (both financially and from a marketing/customer retention standpoint), then they really shouldn't be hosting a team anymore. It is especially hard since it is an unavoidable sign to all that the city is in decline.

I watched this happen in Detroit. They initially lost their team to Pontiac, but got lucky in that their owners did not need the franchise as a source of income and had a strong enough loyalty to the area that they brought the team back to the city even though their were better opportunities elsewhere. Chicago needs the same kind of owner beneficence, but it is rare.