It is very baseless to conclude that Bitcoin will dead by 2106. What you need to know and understand is that bugs found in open source programs or codes can be easily fixed or solved.
Coding the fix is easy, yes. The complication is the hard fork to implement the fix. If we get that bit wrong, it could potentially split the network in two. In theory, it should be a simple update which everyone chooses to follow without argument. But theory sometimes goes out the window if anyone chooses to make things political or otherwise controversial.
And before saying how easy it will be to get people to run a fix which is obviously required, consider the following. Because we want to have as few hardforks as possible, when one eventually does happen, devs will generally want to make the most of that opportunity and include multiple updates and fixes. So it's likely more than one thing which users will need to reach consensus on. They may all agree with the fix, but may disagree on whatever else might be included as part of the hardfork.
