I do not think that IT DD has a stage yet to be significant enough to be conducted. Unless the companies involved are in the IT industry, i dont think that it will ever be considered on the table since there are no perceived “Tangible/intangible” benefits.
I guess it becomes so crucial for M&As of companies operating in the same sector where heavy integration in systems/services is needed to succeed. An example would be the use case of Air India and Indian Airlines.