Stargate would certainly take down Star Wars Asurans, Asgard, and Ori are all very strong, but in very limited numbers. Now look at Species 8472 they can exit fluidic space wipe out a planet in 30 seconds then return to fuidic space while using a mere 8 Bio-ships.
The can destroy planets using an exotic, Chain-raction weapon. The actual energy of the weapon is numerous orders of magnitude below the raw power needed to destroy a planet, as seen in their performance against ships whose performance levels are known be far below planet-killing energy. (Voyager, Borg Cubes)
Which they have thousends of so they can hit hundreds of planets at once.
Not a problem when you only have a handful of planets to protect (Asgard and Asurans) or can become completely nomadic (Ancient City-Ships, and nigh-any replicator construct)
Their weapons have enough brute firepower to bring down anything if used in sufficient numbers,
'Sufficient numbers' here being hundreds of thousands.
-ZPMs store energy on a planet-busting scale. Three such devices are used in the powering of a single City-Ship. Just one is sufficient to operate the city's shields.
-Sustained Wraith bombardment is a noteworthy drain on the power of said ZPMs.
-The Asgard once collapsed a main-sequence star into a black hole, then gave it enough mass to start pulling an Earthlike planet out of its orbit.
-The Goa'uld system Lord Sokar took the once-habitable moon of his capital planet, and bombarded it until the entire surface was a hellish mass of magma and slag metal. He expected to repeat this act in a reasonable timeframe with a single ship.
and know that Ori/Ancient shields are not completely impervious to high energy weapons meaning that Species 8472 could overwelm the limited numbers of hips that can be brought to bear very easily.
As I said until you come up with a way of stopping this your dead.
Having a vastly more powerful navy on alert, ready to engage and destroy any interlopers, complimented by automated defence satelites.
Goa'uld would be assimilated very rapidly by the Borg their tech is very poor, and we know that their damage is vastly inferior to others because of the sacenes of planetary bombardment where we saw each blast was equal to no more than a few hundred pounds of TNT. In other words Trek/Wars weapons have thousends of times stronger.
And yet, when paralell-Earth was atacked by Apophis near the end of season 1 (Or was it 2?) they reported 200 Megaton explosions over the Major Cities which he has destroyed. Can you cite specific examples where Goa'uld ships showed low-yield blasts, and it is beyond reasonable doubt meant to be a high-power strategic bombardment, rather than a more precise assault?
Mark XIs are quite powerfull, but rely on a missile that Trek targeting computers could easily knock down.
When in the entirely of Star Trek has a warship ever shot down an inbound torpedo while in battle? Prove that Trek's accuracy and refire rates will be able to cope with the sort of missile barrages that an Earth warship can dish out.
Earth rail-guns also have very minimal yields, the fact that these yields can damage their shields show that their shields are also very weak,
Sorry, when have Terran railguns done any apreciable damage to an enemy's shields? I recall them being quite useless against anything other than fighters, and unshielded vessels like Wraith Hiveships.
as much as I like Stargate everything will be destroyed the only ones that can toe the line vs Federation Starships, Borg Cubes, and ISDs are the Ori, Ancients, Assurans, and Asgard. Who we know to be in extremely limited numbers.
When you outpower a foe by a few orders of magnitude, you don't need to worry about there being thousands of them. Just more meat for the grinder.