We've known for a long time that American local churches, in general, are moving away from comprehensive Bible teaching and discipleship/equipping for ministry. Churches and agencies together lean on expediency to process potential candidates, sending them to swim in shark-infested waters too immature and ill-equipped for long-term effectiveness in difficult fields.
Short term missions and support of "nationals" overseas are good in their place. But these are NOT substitutes for a steady growth and development of longer-term missionaries from our own midst. These are NOT an excuse to disobey the clear commands to train, send, and support our own people to disciple the nations.
Here's how my friend Bill Taylor states the trend: “I’m not the only mission leader who discerns a dangerous tendency in North America. First we cut down on screening, recruiting, training and sending long-term missionaries and then we just send short-termers. But down the road, we eliminate both short- and long-termers, and we send money instead. At the end we will send nothing! This approach appears cost-effective and less painful at first. But it is unbiblical and perilous for the soul of the global church.” (Global Missions Handbook, p. 128 Bill Taylor)