There are newer currencies that claim to have solved the problem. But the vast majority of them do not understand the problems that Bitcoin is trying to solve,

There are newer currencies that claim to have solved the problem. But the vast majority of them do not understand the problems that Bitcoin is trying to solve, and make security tradeoffs that would be considered unacceptable in the Bitcoin ecosystem. Those that show promise are yet-incomplete. Most don't provide practical scaling benefits greater than 5x, not a strong number considering the amount of scaling we'd like to see is closer to 10,000x.