Yes, people can understand long processes. The degree to which someone understands a complex process depends on several factors including:

• Prior Knowledge: Existing familiarity with the underlying principles or components of the process.
• Cognitive Abilities: An individual's capacity for processing and retaining information.
• Explanation Quality: How clearly and logically the process is explained.
• Level of Detail: The depth of understanding required; a high-level overview is easier to grasp than a detailed technical understanding.
• Experience: Hands-on experience greatly enhances understanding.

For example:

• A software engineer can understand a complex software development lifecycle.
• A doctor can understand the long and complex processes involved in diagnosing and treating illnesses.
• A mechanic can understand the detailed processes of engine repair.

Understanding can range from a basic grasp of the overall steps to a detailed comprehension of each individual component and their interactions.