It's years since I went to Venice, and I thought the gondolas were tatty and dirty (not to mention WAY overpriced) they were then - so if they've gone downhill since then they must all have sunk by now........
Gondolas serve little useful purpose except to part tourists from as much money as possible. I was told they cost about �250,000 so it may not be surprising that they do not have money spent on them. After all, the Japanese and the Yanks will always pay for them regardless.