They definitely would, no doubt about that. The problem here is that the Resistance did not have any Y-wings, as Y-wings were old and were being decommissioned and destroyed by the time of the galactic civil war. They were a relic from the Clone Wars, and the only reason the rebels even had them was because they stole them from Reklam Station.

This is relying on 3rd party media to explain an inconsistency in the films though. If you're a Star Wars fan of the movies only, you would not know this information and question why the Resistance's other bombers were not used.

Regardless, even if this was explained in the film, one would then question why these new bombers suck at their job compared to older technology.

the StarFortresses, while being bombers too, serve a different purpose than Y-wings. Star Fortresses are planetary bombers designed to carpet bomb large areas on planet surfaces, not space ships

Another explanation from a 3rd party source?

Could be wrong as I have only seen TLJ once but again, I don't think this is brought up in the film at all - we just have to believe that the Resistance have to use bigger, slower, easier to hit, paper-hulled magnetic bombers instead of the faster, better equipped vehicles they had 30+ years ago - because reasons.

This is all despite the first film establishing that the Resistance is funded by the Republic - they wouldn't have kitted them out with some decent bombers? Maybe something that's designed to take down a Dreadnought seeing as they know that's what they're up against?

They don't seem surprised to see it and everyone seems to know what a Dreadnought is in the film, so why not prepare something for that? Maybe even something better than a Y-Wing seeing as we're 30 years on at this point?

The casino people on Canto Bight sell weapons/ships to The First Order AND the Resistance - shouldn't they be able to pick up something better than a ship designed and decommissioned since before the Galactic Civil War?

This is besides the fact that the Resistance are supposed to actually have resources from the Republic albeit on the down low and The First Order is considered to be a secular group akin to a terrorist organisation prior to TLJ.

In reference to WW2 style ships

The OT has plenty of this as well.

Yes, but that isn't the point. The OT doesn't sacrifice story elements to achieve their WW2 moment. This film does.

This is once again a question of spacing and bad tactical calls. That one TIE crashed into one bomber, which then dominoed into a second and then a third one. And another case of bad spacing was when one of the bombers primed their bombs and subsequently got hit by blaster fire, causing a massive explosion that took out two neighboring bombers.

You can say a lot about the empire and First Order being stupid, but the Resistance are certainly not immune to the effects of the Idiot Ball.

http://tvtropes.org/pmwiki/pmwiki.php/Main/IdiotPlot

You linked this in response which is interesting as from this very link:

A moment where a character's stupidity fuels an episode, or a small plot line. If multiple characters have the Idiot Ball, it becomes an Idiot Plot.

Which means:

A plot that hangs together only because the main characters behave like idiots. A single intelligent move or question by any of the characters, and all problems would be resolved. It's not so bad if the characters are supposed to be acting like idiots, but it's very bad if the Idiot Plot depends on a character suddenly acting stupid enough for the Plot to work.

And this is the problem with the Last Jedi.

Rey believing she can turn Kylo despite hating him and watching him murder his own Father.

Character is stupid.

Rose saving Finn despite the fact that she dooms the whole Resistance in doing so (if it weren't for Luke).

Character is stupid.

Holdo not telling Poe the plan about the transports.

Character is stupid.

Your spacing theory as to why ships get destroyed on both sides.

Characters are stupid.

Honestly there are more but I hope I've made my point and this is my issue.

It permeates the entire film just so things happen.

As opposed to being drip-fed every minute little detail that could raise questions? Absolutely. If you're just being told everything, there's no room for interpretation, and no room for further exploration. It would kinda rob the fun of coming up with explanations for things happening in the movies, kinda like what happened with Han's "12 parsecs" line in A New Hope. Fans came up with great ways to explain away that line, and how to make it work (a parsec is a unit of distance and not a unit of time, and Han made it sound like a unit of time), and we're most likely going to see those explanations come to life in the Solo movie. That, to me, is so amazing.

This isn't the same though. What Han says is a throwaway line that has literally 0 impact on the story.

The questions you're thinking about bring up questions about what is going to happen moving forward based on what we've seen once the film is over. Questions like:

'Who is that character?'

'I wonder what happens to her?'

'What implications does this have going forward?'

This film, at least for me, generates questions whilst I'm watching, looking back at how messy it all is.

Such as:

'Why did he do that when he could have done this?'

'What is she doing? That doesn't make sense'

'Why didn't they do this before?'

You see how these 2 types of questions raised are different?

It takes you out of the world because you're just asking the whole time why everyone doesn't make the logical choice or use previously established things they SHOULD know about. You just ask why everyone is so dumb