One, the salesforce data changes all occur through APIs (ok) which various enterprise integration tools (Informatica, Mulesoft, etc) support (ok), but those tools typically dont support easy options for retrying a change to a specific row that causes an error. If you are updating 100 Accounts in a single Salesforce Bulk API call and "5" are busy/locked, you have to build a lot of custom error handling to notice and retry just those 5 rows. Its not part of most connectors or python libraries I've seen. Also, 3 of those errors might be fatal and 2 might be retriable but you have to learn which are which or blindly retry them all. In database terms, their API transactional semantics are not statement by statement ACID but row by row within an API request.

Second, no API or SOQL operations can pull back or process or update more than 50,000 rows.

Given those two things, unless the integration person is skilled about both error handling and testing, some of the object busy/contention failures only show up in production traffic with many jobs going on so a generic integration specialist doesn't know about these Salesforce-specific pitfalls and they are discovered after the integration goes live under strange production access patterns.

EDIT: a third issue is that most Salesforce developers are UI-centric in their thinking and training and don't have database or data modeling or data integration experience to draw on so the troubleshooting for data issues on their end tends to suffer.