What would be the number?

[gejohnston]

28. because the media doesn't choose to report them,

and since almost all of them are "no shots fired" it doesn't exactly follow the "it bleeds it leads" business model. the actual number killed by "gun violence" is closer to 8K, since two thirds are suicides. Unless you are going to call the other 48 percent of all suicides rope violence, pill violence, or train violence.............

So what are the estimates as to how many more people would die if homeowners weren't so eager to display a firearm? Would the lives saved REALLY outnumber the tens of thousands currently killed?

Almost all of them are criminals killing each other in places like DC and Chicago. BTW heroin killed 14K people, why don't we hear about those? Gun accidents with pre schoolers are in the double digits nationwide, yet it makes national news, if not international news. Yet the much more common deaths from drownings, drinking drano, medical screw ups, don't make the news.
First thing I learned in Journalism 101, dog bites man isn't news, but man bites dog is. IOW, the more common it is, the less newsworthy it is. That is why plane crashes and shark attacks make the nightly news, but car crashes do not.

In fact, reading the linked report, I see no justification that owning a firearm saves lives. Especially when we already know that the chance of someone dying from a firearm in the home is substantial.

It is really close to nonexistent. The only "studies" that claim otherwise failed any kind of peer review and could not be validated by anyone else.

And yet, every single day people die from guns, and there's apparently no number of these deaths large enough to make very many people seriously reconsider the level and kind of gun ownership in this country. Well, a week ago the murder of some police officers almost got that conversation started, but not really.

Look at some countries where legal gun ownership is almost nonexistent, and have much stricter laws than UK or Australia, like Brazil and Mexico. Their murder rates are astronomical. Then look at countries with gun ownership rates that are about the same as ours, one in three homes, that also allow "assault weapons". Those include Finland, Canada, Norway, Iceland, Switzerland. Some surveys put Finland with a higher rate than ours. There are areas of Norway where owning and carrying a gun is actually mandatory. Granted, it is mostly high powered rifles, but still.
Yet these countries don't have problems like Chicago, Newark, Baltimore, or Detroit. I'm not saying the high gun ownership rate has anything to do with it, in fact, gun ownership has nothing to do with anything according to most criminologists.
What is the difference? Let's take Iceland which doesn't have a military and the police own maybe ten or twenty. Almost all of the guns are privately owned. What else does it have
no poverty to speak of. One percent are rich, one percent are poor and everyone else is middle class. Political corruption is simply not tolerated, and they don't have a drug problem nor do they have gangs.
Let's look at the world's most violent cities, most of which are in South America, but a few are in the US, like Baltimore and Chicago.
What do they have in common?
drug gangs
high poverty
poor infrastructure
political corruption
extreme wealth inequality

“Poverty is the parent of revolution and crime.”― Aristotle

"Laws that forbid the carrying of arms...disarm only those who are neither inclined nor determined to commit crimes. Such laws make things worse for the assaulted and better for the assailants; they serve rather to encourage than prevent homicides, for an unarmed man may be attacked with greater confidence than an armed one." ----Cesare Beccaria's Essay on Crimes and Punishments.

One more thing

Well, a week ago the murder of some police officers almost got that conversation started, but not really.

The conversation has been going on for decades, if not centuries. The problem is that one side is open to having an honest conversion based on facts and evidence, the other simply isn't. At best you will get fallacious arguments and personal attacks, at worst you get "talk to the hand". If you go to any social media for, say, Moms Demand Action, and say "hey I'm a gun owner, let's talk". You will be blocked. When they do talk, they either don't know what they are talking about or are dishonest. Honest conversation is a two way street.