Why some investors fail to generate promised returns to lenders?

[Vijay Kurhade]

Majority of real estate developers use external funds be it equity/debt as high as 70-90% of total project cost in some cases, even though industry has various risks be it inflation, market conditions, finance, sensitivity but then there are many experts and technological tools, advancements to guide through various stages of project from inception-design-planning to execution and conclusion;

Despite of all this, we keep reading about many developers fail to generate promised returns to lenders, few cases matters even become very sour to litigation, in turn making real estate investing as risky as it was decades ago.

If business uses outside funds which is more available than earlier, what could be top reasons fair amount of projects fail to generate accepted returns(very common in developing countries).

Thanks in advance.