Is there any possibility of a decrease in demand for Bitcoin? Whatever happens, people give up using bitcoin.
Of course it is possible. As much as it is possible that the demand can grow high, the opposite can also happen.
A few reasons that can effect this are:
1. Bitcoin fails to scale
2. Bitcoin is banned from your country
3. Increased confirmation time
4. A better alt coin emerges that overshadows bitcoin.
5. A major bug is suddenly found on bitcoin codes
There can be more reasons that can bring the demand down that I have not thought.
I am really sorry but you are completely mistaken;
1. Bitcoin will succeed to scale with either the one or the other way. Nobody and especially miners want people give up bitcoin because they have spent millions of dollars in mining pools.
2. So what? Bitcoin uses internet and anybody can use it to buy things from Internet. Moreover banning has the opposite results from the intended ones https://news.bitcoin.com/needham-banning-not-prevent-bitcoin-adoption/
3. There is lightning network in alpha release for micro payments
4. May post the traits this alt coin so as it will overshadows bitcoin? or what kind of features bitcoin lacks from this super alt coin?
5. Wow!! After 8 years nobody found this 'bug' and 'major' one? If anyone find something like that banks will put him on their payroll without doing anything.
Today I read that Pakistan the 7th most populous country in the world may be the next major user after India https://news.bitcoin.com/pakistan-set-to-become-a-major-bitcoin-hub/