there are too many variables in business processes, computer software, hardware and the operating systems for all bugs to be found

This statement is generally true due to the following reasons:

1. Complexity: Business processes, computer software, hardware, and operating systems are all complex systems with numerous variables. Each variable can interact with others in unpredictable ways, leading to potential bugs.

2. Interactions: The interaction between different software, hardware, and operating systems can also lead to bugs. For example, a piece of software may work perfectly on one operating system but have bugs when run on another.

3. Continuous Updates: Software and operating systems are constantly being updated and improved. Each update can potentially introduce new bugs, even as it fixes old ones.

4. Human Error: Humans design and implement business processes, write software, and build hardware. Human error can lead to bugs in any of these areas.

5. Testing Limitations: It's impossible to test every possible combination of variables in complex systems. Therefore, some bugs may not be discovered until after the product is released.

6. Time and Cost Constraints: Thoroughly testing a product for all possible bugs can be time-consuming and expensive. Often, companies must balance the need for thorough testing with the need to release products quickly and within budget.

7. Unpredictable User Behavior: Users may use software or hardware in ways that the designers did not anticipate, leading to bugs.

In conclusion, while it's theoretically possible to find all bugs in a system, in practice it's nearly impossible due to the complexity of the systems, the interactions between them, continuous updates, human error, testing limitations, time and cost constraints, and unpredictable user behavior.