Many of the patterns that are described in this wiki require some up front investment. The cost of the investment can either be direct in terms of added work or indirect through reduced business value in a release. The value of the investment is in reduced risk of failure or rework.
Investing in a MRP strategy is very similar to the development practice of refactoring. The reason developers refactor is that by cleaning the code it becomes easier to maintain. Refactoring is therefore an up front investment with long term benefits.
In Replacement projects there will often be an unwillingness to invest in changes to the system being replaced. The intuitive feeling is that these investments are a waste of money since the system is going to be closed down. This is unfortunate since many highly effective MRP strategies require that some changes are made to the legacy system.