Why does Japan need missionaries?

Here is a link that's been going around my Japan-missionary Facebook circles this week. It is a well written explanation as to why Japan needs missionaries, why Japan is a significant mission field, even if it doesn't fit the usual criteria.

My only beef with it is this little bit at the end where he says:

Why is Japan’s Christian percentage so low? My simple answer is that: Japan needs more Christian workers. We urge you to “pray earnestly to the Lord of the harvest to send out laborers into his harvest” as it says in Matthew 9:38.

It is too simplistic an answer. It suits his need to call for prayer and support, but it isn't the whole truth. But, to be honest, I don't think anyone except God knows why.  It is something that is frequently talked about in missionary circles here, but I've not yet heard an clear answer, only conjecture.

On a lighter side, here's a shocking statistic:

Tokyo is the world’s largest metro area, with more than 35 million who live in its metro area. Tokyo’s metro area population is roughly . . . 50% greater than . . . Australia. 

That's why it took us 15 minutes to drive 3 kilometres this morning! Of course, I keep forgetting.

But his conclusion is the same as my own prayer:

Our prayer is that the Lord would provide more workers for His great harvest here in Japan not only for our ministry but for all of Japan.