The only time we've seen a thousand ships or higher in any canon (Legends or Disney) attack a planet was the Battle of Coruscant,
So, by your own statement, we have evidence the Galactic Empire can marshal a thousand ships for an operation should the situation call for it disproving your earlier, baseless assertion.
The doctrine in Star Wars prefers lots of smaller fleet attacking several planets at once
Which makes sense against a peer opponent that can maneuver and react as quickly as you can. Obviously that wouldn't be applicable in this situation.
I mean by that logic the Imperium kinda does too
I haven't really discussed Imperium fleet numbers, its largely academic since its doubtful they could ever coordinate their fleets to take advantage.
The idea is that even if the Imperium, in total ship strength, were four or five times the Imperial fleet size the GE would still be able to achieve tactical numerical superiority and just overwhelm them. So the closer the Imperium is to parity with the Imperial fleet the worse the situation is for the Imperium.
Imperium fighters are the equivalent of Galactic Empire cruisers and yes they are still fodder
Here makes mention of a Fury Interceptor being 70 meters while
a Carrack light cruiser is 350 so since ton for ton the two sides are equalized a carrack cruiser should do more than a bit better than a Imperium fighter. Further the point is if they can deal damage to Imperium ships, which they should, then there is little reason not to use them. It isn't like the Empire cares about individual losses and such ships already have ships and crews. Their cost would be negligible compared to not using them
Literally fanon, the GE has never been that competent or efficient
Actually we do have evidence the Empire can and will scale up ISDs to fit the mission parameters. Witness their use of 3 above tattoonie versus six above Hoth to approximately 30 at the battle of Endor.
I mean hell there should be Clone Wars veterans still serving in the fleet who remember the battle of Coruscant so the idea of amassing huge fleets shouldn't be that alien to them. Assuming the Imperial fleet is crewed by anything more than chimps would make it the logical move.
The GE couldn't mobilize hundreds of ships to stop the Rebels from escaping even with Vader himself present and minutes to hours of fighting.
Which proves what, exactly? The Empire can't conjure up hundreds up ships within mere minutes?
Not mentioning that without Hyperspace coordinates the GE wouldn't be nearly as fast outside of their mapped territory.
Actually in Disney canon it isn't that difficult to map a new hyperspace lane. I can post you the quote if you like but suffice it to say they will handle that far easier than the Imperium will venturing beyond the Astronomican.
It wouldn't need to hold most of its fleet though, the light weights of the Imperium are on par with the Galactic Empire's heaviest hitting ships.
In any rational analysis, yes it would. Its fighting a foe that can attack anywhere virtually instantly from its perspective. Every system it doesn't want to just vanish would require fortification enough to ward off an attack by hundreds if not thousands of ISDs or tens of thousands of lesser vessels which starts eating up your navy very, very quickly.
Your argument is essentially bragging how a King Tiger can take out so many Shermans while ignoring bigger canons and thicker armor rarely are as pivotal as getting where you need to be, when you need to be in enough quantity to get the job done.
So you posted evidence proving planet based defense systems are a thing in Star Wars...and Star Wars one are far more effective having a magic disable ship ion cannon to a pedestrian Laser canon.
They can't BDZ a planet from far off distances they're always close, close enough that Defense Lasers will mulch them.
Actually since they can drop out of hyperspace essentially in range for a bombardment, ala Hoth, considering Imperium reaction times and sensor tech it isn't a certainty they'd even have time to get a shot off before they planet was being bombarded.
Further you don't need an ISD to bombard a planet. I believe a Victory can do it nearly as good so isn't like the 25,000 ISD are the only pool they can draw from. Not to mention, unlike the Imperium, the Empire can actually replace it losses where as the Imperium takes decades to make a new ship when it can. Obviously the number of old ships in their fleet suggest they have a limited industry.