It seems that bear-bating in Elizabethan England could be seen as their version of Roman gladiators. It would be interesting to try and find some equivalence (if one expected) for most other eras of history. One can make arguments for soccer and reality TV in the modern era (or TV in general, I suspect), but the visceral thrill of watching people be executed or hanged at the gallows seems to have been resigned to the past. On a basic level, every society needs values to let pressure escape from them, some being obvious and others much less so.
Religion counts as well, since one can argue that its primary purpose is social control/conformity. That's not to say it is what religion is about, but effectively what it becomes as a tool to maintain social order. If you want to avoid a revolt, you make sure people can't even conceive of it or convince them that they will be vindicated in some future time (via heaven/reincarnation/the dead all being equal and so forth).
The more obvious and gruesome spectacles to distract people also serve as warnings, much as being called a witch did in times gone by -- they told people that this is what happens if you screw up and warned them against stepping too far out of social norms. That betting on them is also the norm and can allow one some measure of wealth and perceived control over their lives is definitely an important factor in such events, but the fact that they become necessary for a society could be considered to imply a breakdown or at least symptomatic of a massive change in said society.
Elizabethan England was having the Protestant/Catholic wars straining ideas of what it meant to be of one faith or the other, and the price of conversion vs. that of souls, whether the nation could be considered godly and so forth, while the Roman empire was bursting with slaves and falling apart at the seams. I suspect that a society with less discrepancy between the rich and the poor in terms of wealth would require less overt or obvious means of social control, but it is likely a difficult theory to study.