According to research if bitcoin reach its limit, it will be disappear but it doesn't happen already so don't worry. I think devs will solve the problem to extend.
Where is this answer coming from? I wonder what research paper you read because it is definitely not in bitcoin's whitepaper.
One of the options now is to develop bitcoin. In the future there is an issue stating that there is a new type of bitcoin that will be outstanding. But it is still limited to requests from several communities only. We'll see later, but I still like the bitcoin that exists today. Changes can sometimes lead to good, but sometimes can make things worse.
That is an altcoin not bitcoin