If governments ever endorsed it, I'd be kinda suspicious about their endorsement. Bitcoin is not something they want, so endorsing your enemy is against my logical way of thinking. I feel like we take these elections too much into account when speculating Bitcoin's price. Biden's support is obviously necessary if we want Bitcoin to grow under his governance, but it's not required. Bitcoin goes on its own path.
Why people might choose to abandon it is a different question, but it is entirely possible
There are reasons such as something better than it popping up. If nobody thought of the idea of Bitcoin before (or thought about it but never put it into reality), we may not have any idea what other decentralized currency could be coming up soon. Maybe something that will be more fair than Bitcoin, more decentralized, more flexible and scalable, under a different structure than blockchain and much easier to use.