Would a weekly televised Impact Wrestling, Ring of Honor, Lucha Underground, & Defiant Wrestling joint show fare against the WWE?

WWE.

The problem isn't talent. All 3 promotions have enough talent to make any of them a low level draw. The problem is having your name out there and having production that can match a WWE show. Lucha Underground has/had the production, and they got a, pardon the phrasing, underground following but as long as they're on El Rey they wont make enough noise. ROH has a great roster with New Japan ties along with a 16 year legacy of producing the next big thing, but TV sucks in how it's booked and how it's presented. Defiant's flat out a local indie standout with zero national TV (if any at all. I'm not in the UK) and only a dirt sheet that's lost a vast majority of it's fan base due to infighting and a content creator mutiny. Impact Wrestling is a revolving door for talent to the point that the only person I'm safe to assume is still there since I quit watching is Abyss. They're on a bad network with very little in the way of a reputation in the mainstream, and what reputation that is there isn't good due to the backstage being almost as anarchic as the TV product.

So out of the four you have three confirmed Nationally broadcast TV shows, two of which lack structure, and one of which lacks exposure outside of Netflix (which they gain nothing from but eyes on the product) and El Rey, that is when they're not between seasons a vast majority of the year, and even there you have budget cuts affecting what makes LU special.

Not well because I know people who if they watch Professional Wrestling only watch WWE and won't watch anything else. If anyone wants to prove me wrong then they should start watching Ring of Honor and Impact wrestling who both have weekly shows that are on every single week.

No

Impact Wrestling maybe. Ring of Honor and Lucha Underground plus Defiant Wrestling are still Independent Circuit-based wrestling leagues.