This will increase the price of coins, but you need to improve the system so that there are no failures due to a huge number of transactions.
I agree. And I think that the bitcoin blockchain system can never maintain a huge number of transaction daily if the whole world starts using Bitcoin. There will be another altcoin strong enough to sweep Bitcoin away
Well currently it's fair to say that but what if there's a solution for a possible change in block size which will be agreed by all ? That's why I hate conclusive statements because nobody knows tomorrow.
If you think the whole world will use it, I'm sure that they will try to catch up to to the furthest development for of the bitcoin project. People all over the world, programmers, developers etc will combine all knowledge to make an extraordinary update for bitcoin. Why would the whole world use a limited blockchain system?

That is the only problem for bitcoin to be used in all nations of the world; being limited in terms of supply. If bitcoin was unlimited to its supply then there is possibility to be adopted by the people around the world and their nation. But the disadvantage for that is bitcoin will become cheaper and more stable which most of us don't link because one of the things that make us interested in bitcoin is its price and being volatile.