Some Future Scenarios - One Very Happy One

The very happy scenario is that Westerners turn their huge force of industriousness they posses, as can be witnessed in the leading role of massive material welfare gains for the last centuries, into spiriutalizing the West (compared to the industrializing of the West that took place.)
This means that Westerners will start a successful spiritual journey on a massive scale. This possibly requires the invention (which is a core aspect of industrializationing) of new ways to be spiritual.
This spirituality must be free of political powerambitions. It respects individuals freedoms and rights, the practice of homosexuality, equal rights for women and treats people of all religions equally.
This spirituality then is the foundation for larger numbers of non-Muslim babies born and attracts Muslims to convert away from Islam to the new spirituality, all over the world.
If one have an idea of how the fabric and actions of a massively spiritualized West would look like, one could tell the feasability if this vision. But who can really say what it would be like? One way to get inspiration for visualizing it would be to take part of the book/audiobook "A New Earth" by Eckhart Tolle. According to my vision based on that book, the society would be peaceful and act from emotional awareness and honesty.


Three other, not as happy scenarios:

There are two when non-Muslims act to ensure that they or their decendants will never live under Sharia law.

One scenario is that the majority of the population declares that a part of their own country will become a Muslim souvereign country and forces Muslims (perhaps that are not both fully westernized and anti-Sharia) to move there. In the remaining of the country, it is made forbidden to practice Islam.

The other scenario may be done if all countries in the world are under Sharia rule, but it is permitted to move to another country. In this case such a large number of non-Muslims may move to the same country that they become in majority and then splitting the country and making the actions as in the first scenario.

Some has speculated that Muslims could be mass-murder in Europe, in the socialist 2000 - th century style (nazism, communism). These first two scenarios may provide roughly the same benefits as the murderous one (I guess) but with less (but none?) violence.

Possibility: Islam is getting competition from a new religion

Since Christianity started 2000 years ago it has spread enormously.
Islam is a religion that is newer than Christianity. Since its start Islam has increased more than Christianity because Islam is designed that way. Islam is designed to be more expansionistic than Christianity.
The method of Islam is aggressive, for example the intimidation of non-Muslims and subjegation of Muslim women. The driving force in Islam is aggressive males that are not out-of-the-closet gays (gays are hanged in some Muslim countries, as evidenced in the film Fitna which is free to watch on Youtube (warning, it is scary)).
A new religion has a place in time to emerge. A religion that offers things that Christianity and Islam doesn´t. It is individualistic because collectives, also spiritual ones, offers the individual an identity which is false. The religion doesn´t present dogmas, like "do that" and "don't do that". The religion is the one started by Eckhart Tolle, I think called "A prophet of out times" by Oprah Winfrey.
Because the new movement is individualistic it is difficult to subjegate it.
I feel that Islam is comic in the eyes of a person that is living in the Now. A religion that is comic doesn´t have a chance of flourishing.

Also, for non-spiritual individuals, there has emerged a "religion" that fits them. That is the "religion" of Ayn Rand. This is also an individualistic "religion", and therefore also hard to supress.

A Positive Thing About Islamists: They Put Up a Interesting Fight

A positive aspect about that there are Islamists is for those of us that like a good fight. "They are worthy enemies" (Daniel Pipes is quoted, but I am unsure if this is a fully correct quotation), and with worthy enemies there will be a good match.

One Reason for Hope

Hope is vital for humans. It´s like having oxygen in the blood.

One cause for hope regarding the West surviving and limiting the negative effects of people following Muslim law, Sharia, is that if there will be more Muslims in the West than today, Westerners is confronted with a challenge. The challenge is how to deal with the new situation and the circumstances it produces. This challenge will make a lot of people look into what values are true. It will be a philosophical quest and also a spiritual quest for many Westerners. This will make Westerners even more evolved as human beings. Many of them will decide also if what they believe in is worth putting in action and worth taking a stand for.

What is hopeful with this is that when Westerners in this way develop to the highest form of human beings that has ever existed they will act in ways that is difficult to predict today. These actions may very well be very good and successful, leading to a wonderful world to live in - it is simply impossible today to tell what Westerners will be like when they are even more evolved and what they will do. Not only actions but being itself may produce positive effects: Eckhart Tolle says in The Power of Now (the audio book) that more consious persons make positive effects in less consious persons.