I like to keep things simple. The arguments in favor of residing in galus over Israel inevitably boil down to two tracks:
1) Life in galus is better.
2) Life in Israel is worse.
The rest is commentary. People will only move to Israel, or choose to stay there, if they crunch all the objective and subjective variables, and determine that life in Israel is a better deal. There is no need to catalog all the variables; we know them.
Instead, I would like to present the greatest sales pitch for galus in history. Imagine a scenario in which life in galus could not be any better, while life in Israel could not be any worse. It would look something like this:
Economic: Getting by in Israel is virtually impossible. The economy is completely in the tank, extreme poverty is widespread, and there are severe food shortages. Survival is only possible due to an influx of foreign aid, which of course comes with strings attached.
In galus, however, the Jews live with great prosperity and don't even need to work. Their standard of living could not be better. They are free to live in the most upscale neighborhoods, tax-free, without even having to worry about zoning laws.
Political: Israel is completely ruled by gentiles. In fact, it wouldn't even be known as Israel. Not only are Jews an extreme minority with little political influence, there are no Jews there at all! Although Jews are allowed to live in Israel, they have no say in how the country will be run. Furthermore, the gentiles who rule the land are diametrically opposed to Jewish values, and any Jew who does live there would need to keep an extremely low profile. He would be grudgingly tolerated at best, and would need to be perpetually wary of his neighbors.
In galus the Jews enjoy political power at the highest echelons and can be openly Jewish with impunity. Although there are some resentments, in general the Jews are respected, admired, and feared by the gentiles. No one would dare lay a finger on them.
Spiritual: Life in Israel is a spiritual wasteland. There are no rabbis, no shuls, no yeshivas, no Jewish education, no communal infrastructure of any kind. How could there be? There are no Jews! But to make matters worse, the spiritual environment could hardly be worse. The gentiles who rule the land are morally bankrupt, far worse than the gentiles in other lands. Raising a proper Jewish child would require separating from society as much as possible, with no support group.
In galus the Jews would still be vastly outnumbered, of course, but they would be able to live in their own spiritual cocoons. They would be guided by tremendous tzaddikim and Torah scholars, among the greatest who ever lived. Jewish education would also be completely free. Their religious rights would be fully protected; in fact, Jewish leaders would be recognized as holy by the gentiles and held in the highest esteem. Naturally, Jewish communal and family life would be ideal.
If a Jew could choose between living in the Israel or the galus described above, the correct choice would be obvious.
This is not a theroetical question. This actually happened. When the Jews first came to Egypt, and for many years before things turned bad, this was the situation. Yosef was the ruler. Yaacov was the spiritual leader. The Jews enjoyed freedom and prosperity without a care in the world.
At the same time, Israel was known as Canaan, ruled by the most wicked idolaters in the world. They were so spiritually bankrupt and morally corrupt that they deserved to be utterly destroyed. There was famine in the land, and everyone was beholden to Egypt for their food. The inhabitants were also well aware of Jewish ambitions to ultimately kick them out and take over the land. Conditions for a Jew could hardly be less favorable.
Nevertheless, Yaacov would not have left Israel were he not compelled by divine decree and heavenly machinations. Same for his family, which comprised the entirety of the Jewish people. Yosef would not have left Israel or remained in Egypt if not for circumstances beyond his control. They were expected to live in galus at all times with one foot out the door, ready to return to Israel at the earliest opportunity. They were expected to give up the best life in galus for the most difficult life in Israel, and to view that as the greatest priority, the greatest blessing.
Home is home, and if it isn't everything you want it to be, you need to be there to really change that.
Despite all the complaints, many of which are justified, life in Israel has a lot going for it. Despite the deep attachment many Jews have to galus, despite the yetzer hara to remain there no matter what, life in galus is no paradise for an authentic Jew. It never can be. It's an exile, an unnatural habitat, a temporary dwelling where the Jew may be tolerated and exploited for some time, but where he is never meant to feel at home. He doesn't belong there.
When a Jew remembers this, keeps one foot out the door, and desires to return home at the first opportunity, there is no need for the galus to be rough. However, when he mistakenly interprets God's kindness in softening the exile as a sign that he should plant both feet there, the kindness needs to be removed.
One final time, as has happened so many times in history, the Jews have planted both feet in their temporary dwellings, mistaking a comfortable life in galus as preferable to an uncomfortable life in Israel. The kindness is being removed and once again things in galus are turning very bad very fast.
It shouldn't have to be this way, and it still doesn't need to be this way. We can learn the lesson without having to learn it the hard way. We can turn things around and finally get it right.
Tell shmutz la'aretz that you appreciate the hospitality and will remember the good times, but it's time to just go home.