Yes, of course! No one expects a bunch of western weebs to save Japan's demographics. Obviously, Japan will have to change their insular culture and work ethics, if they attempt to deal with the problem by significantly increasing immigration.
Yet there are many western countries where the issue is how to prevent all the people attempting to get in from doing so.
The people America is trying to prevent from coming in are largely low skill, low education, generally do not speak the language, and so on. These people are no more a solution than our idealistic weebs. In most cases, they're rather worse off since weebs at least tend to have language and other skills, but are trying to move to a place that doesn't exist.
> The people America is trying to prevent from coming in are largely low skill, low education, generally do not speak the language, and so on.
US also put a lot of roadblocks in a way of highly skilled immigration. For example, check the waiting time of Indian engineers to obtain Green card.
> These people are no more a solution than our idealistic weebs.
Not sure I agree with this assessment. Unskilled immigrants tend to be over-represented on hard low-paying jobs, both in EU and US. Someone has to build, pave roads, cook, deliver, tend of elderly, etc.
You've gotta separate cause and effect, especially when these things will change in the future. For instance decades ago I had family that worked in construction. They were earning about $20/hour in a rural area back when that was quite a lot of money, even in an urban area.
It was enough that, even with the on-off nature of the work (you're not getting paid when nothing's getting built), they could easily raise a large family very comfortably. Now a day construction in the US pays awfully and a big factor is the large number of illegal migrants working in it for sub-market wages. So you're talking about the necessity of solving a problem by expanding the thing that caused it.
It's very difficult to predict what demographic collapse will look like in a place like the US, but one general trend that might inform us is that fertility within places like the US remains strongly inversely correlated with income. Those who are earning a lot aren't having children, those who aren't earning much - are. Pair that alongside fairly low upward mobility, and again I think it's unlikely that significant numbers of unskilled workers will have any real value in the future (or present).
Yet there are many western countries where the issue is how to prevent all the people attempting to get in from doing so.