The SE won because of their Force users (I still question that decision but it doesn't matter) and last time I checked, Mandalore didn't have Force users. Not only that, but the Mandalorians pretty much fell apart when Revan and the Revanchists joined the war. They still put up a good fight, but there was a clear change in momentum when Revan joined the war.
Grievous was able to fight a war against some of the most powerful Jedi ever. Not only that, but Grievous was able to keep up with the massive shipyards of Kuat and Rothana. Mandalore faced a Republic that was still damaged from the devastation that Exar Kun brought about during the Great Sith War. No one questions the capabilities of the Mandalorians, but they didn't face the monster that was the Republic industry at the time of the Clone Wars. Grievous was able to force the Republic to spread its forces thin across the galaxy.
The Mandalorians would be confronted by an unlimited number of battle droids, heavy assault vehicles and fleets that could contend with some of the most powerful ships constructed. Mandalore doesn't have Force users like the Republic. He doesn't have billions of soldiers. And he doesn't have the industrial might to to stop Grievous.
We know Mandalorians can beat the standard B1 Battle Droids, but can they stop the merciless assault from AAT's, Hailfire droids, Spider Droids, Dwarf Spider Droids etc.? No. He just doesn't have the forces to do it. Each battle (even a victory) is going to wear down Mandalore's numbers. The casualties stack up, especially when you don't have limitless numbers like the CIS. Losses don't matter when you can simply make more. Mandalore doesn't have that luxury.
Not to mention the fact that Grievous can just send Ventress to kill Mandalore and Fett. And she can kill them.
Mandalore wins a few battles, but he gets overwhelmed by the sheer numbers and production capabilities of the CIS.
Way to kill my post Aurbere
. Anyway, I definitely agree about the two scenarios brewing. I can totally see where you both are coming from.
Now to Ventress. She will be the factor that decides the fight. If she was to assassinate Mandalore, there would be spots that Mandalore could win. Notably if he was able to knock her second sabe away from her Ventress would be at a disadvantage. Also, she fought with Makashi and Jar'Kai, which would only really help her if in a duel(I don't know for sure). Also, if she was to fail, she hated criticism, which she wold most definitely receive from Grievious. If he pushed her enough, Ventress could fight him-something she has done before, and won.
Sadly, I don't see it being that easy. I think she might just kill Mandalore and end the Kaggath. Any help here fellow Mandalorians?