I wouldn't discuss with that part, although there are definitely limits to how big a chunk of a big product a single brain can really grasp technically. And when the number of people involved in "grasping" grows, so does the coordination/communication tax. I digress, though.

We could go with that perception, however, only if we assume that whatever is in the backlog is actually the right thing to build. If we knew that every feature has value to the customers and (even better) they are sorted from the most valuable to the least valuable one.

In reality, many features have negative value, i.e., they hurt performance, customer satisfaction, any key metric a company employs.

The big question: can we check some of these before we actually develop a fully-fledged feature? The answer, very often, is positive. And if we follow up with an inquiry about how to validate such ideas without development, we will find a way more often than not.

Teresa Torres' Continuous Discovery Habits is an entire book about that :)

One of her recurring patterns is the Opportunity Solution Tree, which is a way of navigating across all the possible experiments to focus on the right ones (and ignore, i.e., not develop, all the rest).