I disagree with you. Mike is not the only talented member of the band. I really hate when fans say that. Yeah Mike is super talented and probably the most creative and talented member, but he is not the ONLY talented member. Each member brings something unique and amazing to the band, that's what makes Linkin Park so awesome. Mike could never sing like Chester, for example. Chester has a very unique, amazing voice, that's loved by many people. Brad is really good at creating LP's sound and always brings interesting ideas to the table. Rob is really good at drums and I don't think anyone else in the band could ever drum like he does...he also basically created TLTGYA which is IMO, one of LP's best songs they have ever written. Joe and Phoenix also contribute a lot, it's just not shown or talked about a lot.
Anyways, I don't think it's their confidence or anything either. The band seems confident in everything they have done, from MTM and up. They make the music they want to hear, and hope the fans understand and appreciate it. ATS is living proof of that. The reason the band takes so long to release new music is because they are all perfectionists, they've all said that multiple times. They don't like to release albums if they don't feel like they did their best and it's complete. Same idea goes for random singles and EP's. They're just not that kind of band, and probably never will be.