Pilots know the feel of the yoke. They should have also noticed during taxi the yoke not at neutral during trim check. The case was preventing full forward input meaning it was used to keep the stabs at neutral or full aft. If they normally taxied at full forward it would have seemed wrong at neutral or full aft. A complete cycling of the yoke and flight control check would have caught the case deflecting the yoke 100% no doubt about it. Being in a hurry and skipping routine checks doomed the crew.
No point of debating. The restriction could have been a lot or a little and a little may have been just enough. They made a mistake and paid for it and so did others. We’ll never know if they skipped the checks or not and just didn’t notice the difference in their haste.