This is somewhat opinion, but as previously mentioned, it's because of a difference in standards.
Is there an aircraft that can seriously challenge the F-22? Pretty much no (if the PAKFA lives up to all it's expectations, then it may present somewhat of a threat).
Is there an aircraft that can seriously challenge the F-35? Sure; the PAKFA, J-20, J-31, the Su-35S, etc are all competent machines with a lot of capability.
Are they greater than the F-35? In some areas, particularly kinematic areas, certainly.
Will they be more survivable and capable than the F-35? The answer is uncertain due there not having been a war to put the relevant systems head-to-head, but according to the leader in air supremacy and aviation doctrine, the F-35 will be superior in combat when fielded in a realistic and operational manner.
With that, keep in mind that as a couple have stressed, the F-35 is but a system within a system. The aircraft never kills the enemy (so to speak), it's always the bullet / missile, guided by the aircraft, controlled by the pilot, informed by his sensors, directed by early warning and C3 systems, etc.
Each is a multiplier of force projection, and if you don't develop each one without thinking of the others, then you're not doing yourself a favour. The F-35 is a case where they have put a lot of thought into system integration.