The term in parentheses expresses the idea introduced by the term in bold in

"Instead, they made radical changes to their initial models," - lines 3-4 (replacement).

"Unfortunately, they are usually wrong." - line 15 (reason).

"Alternatively, some good ideas take something in customers' lives that's pretty boring." - lines 45-47 (cause).

"Next, you'll need to identify some analogs," - line 50 (exemplification).

"beliefs you hold about the answers to your questions despite having no real evidence." - lines 64-66 (consequence).