My owner's manual has no mileage recommendation. By changing the oil when the oil life indicator advises to, I am following the owner's manual.
I don't know how old your Toyota is or what system it uses, but on many older vehicles you are quite correct that the oil change reminder is based on mileage alone. Older vehicles didn't have the ability to monitor engine operating conditions in an effective enough manner to allow a reliable dynamic recommendation of oil change intervals, so it was based on an arbitrary fixed mileage interval.
With any modern vehicle that is equipped with an oil life monitoring system, applying the same maintenance program and changing the engine oil based on mileage alone at relatively low intervals like 5,000 miles is something that many people continue to do. This mostly results in unnecessary premature oil changes. These are not only wasteful of both money and resources, they do not provide any appreciable benefit to the engine either. Modern engine management and improved engine oils have increased oil change intervals significantly. The intervals suggested by the oil life monitor cause me no concern.