The major governments of the world have for some time been laying the groundwork for their own national cryptocurrencies. Does that matter? Yes, it matters a lot. Bitcoin will be a direct competitor.
Why do they do this? To remain in financial control and to stop financial crime like whitewashing of funds from happening. Is it likely to happen? Yes, the US banned holding gold privately in the 1930's. So that the US government was to be a monopoly gold holder in the US.
There is a clear danger that the US, Europe, China, Japan and others will get togheter and flat out ban and even criminalize the usage and holding of Bitcoin. Resulting in after the ban, if you are cought using and holding BTC, you would get a huge fine or jail term.
The price of Bitcoin would get killed completely, you would be looking at Bitcoin below $1000.
How likely do YOU think this scenario is? Although you might say this is only speculation, IT IS A FACT that these countries are working on cryptocurrencies of their own.
As they already said, users/investors will not shift to another digital currency just because they've made or adapt the system of cryptocurrency. It's very impossible for them to bank decentralized money since they don't have control over it we have multiple ways of accessing it. Killed? It is too much.
A cryptocurrency even a shitcoin can't be killed, they can lose value but can't be killed as they were created and already existed in the world of crypto. Imagine, a shitcoin still exists in the blockchain, what more in bitcoin? thousands of users, a huge community, and a lot of investors.