All my architects are over 40, every single one of them.
Working on a 10 year old code base, multiple stacks (mobile apps, Java backend), on AWS.
You need clear headed people that know how to spot bad stuff about to happen and then clean it up, keeping the big ship stable. Constantly removing technical debt.
SaaS is the best thing that ever happened for job stability for engineers. Constant updates, upgrades, etc. The guys at Salesforce.com, Workday, ServiceNow, etc have a long road ahead of them.