B777,
Rest assured that you weren't too far off the mark! Yes, you could have been more assertive/forceful - but at what cost? You opted to keep group harmony with what you thought (correctly) was second best. In the real situation that was a reasonable, and (without details) I think best solution. Unless the item was essential - in which case I am sure you would have been a lot more forceful- you are better off.
If you really are on that sinking ship: your companions will kill you a lot faster than the lack of almost any piece of equipment. The group may not be correct 100% of the time, but they are all you have at the time.
Next time, trust yourself a bit more, use a bit more authority, but stay in the group - unless they are going to Jonestown. Ultimately, you just have yourself and your own judgement.