The second part of the answer is open source. Open source commoditizes the stack. MySQL replaces Oracle. Linux replaces Windows. TomCat and JBOSS replace Websphere and NetWeaver.
Not if the customer has already installed Oracle, Windows, Websphere or NetWeaver. Any solution that does not work with the customer’s present system is no solution.
One of the reasons I promote the work of the Federal XML Work Group is that the collective buying power of the federal government has the power to oblige vendors to build interoperable products.