Currency failure generally occurs due to the type of hyperinflation, and there is always the potential for technical failure, currency competition, political issues and so on. As the main basic rule, there is no currency that can be considered very safe from failure and difficult times. so is it possible that bitcoin can become worthless?
Yes for sure, you have yourself mentioned the main reason why bitcoin can become obsolete and that is technical failure. Bitcoin works on such a blockchain network which has quite a lot of traffic. Moreover, we have seen a lot of scalability issues with bitcoin in the past. If it become unuseful as a currency then obviously soon it will loose its charm as an asset to there fore reducing the prices and ultimately becoming obsolete.