Silverware, napkins, and drinks are the responsibility of the person/s designated by the restaurant. Since (a) we don't know who in this location is responsible for placing the napkins and silverware on the table and (b) surely in the time this party waited for their food they could have asked someone on the staff for the missing items, we can't say for sure who to 'blame'.
The soft drinks in most restaurants the servers can get them at the soda stations, which at a lot of chain restaurants for example, they may have at least 2 or 3 soda stations available. That is not a bartender issue in most restaurants.
The silverware and a napkin is initally usually the hostess's or host job, but if they don't do, it becomes the server's job, because the customers aren't supposed to get their own utensils, should they? They shouldn't be serving themselves the basics.
I can say for sure who is to blame, the LAST PERSON to notice if there is no utensils and is getting paid to notice this, which is the SERVER, NOT anyone else. It doesn't matter who is at fault initially, it only matters if the customer receives the mistake or not, because if the server can prevent the mistake, that prevents the forgotten silverware/napkin/refill, which prevents problems. That makes the service have no problems, so WHO do you think is at fault now that you see it through common sense?
It's always the server's fault if you don't have utensils unless there aren't any ones to clean available. I have had a waitress once serve me and my husband side salads and told us since there was no clean silverware, SHE had to go clean some. She didn't depend on the kitchen staff. She tried to make her own tip. We sat for at least 3-4 minutes waiting to eat the salad with no forks. The point is, if she had the attitude you have, we wouldn't have been eating our salads. We would have received our meals before getting any utensils even depending on "it's someone else's job, not mine" attitude.
Soft drinks/tea/water are ALWAYS the responsiblity of the server unless there are no soda stations, which there are some restaurants that you have to go to the bar to get soft drinks, but they are rare in general.