Because you are not thinking like a board member.

You have an IT system that has been in place since before you were hired. Let’s be generous and say it was developed in the 90s and running on an AS400. All costs are accounted for and is costing $400k a month, the platform is working as intended and staff are adequately trained. The platform is rock solid and you don’t recall the last time a catastrophic failure happened.

Your IT underling comes to you one day and says we need to change this business critical and it will cost $1.2 million as a Capex with an ongoing opex of $600K a month. it will take 4 years to develop, another 6 months to migrate the data between systems and take another 4 months to train staff back to a basic level.

How in the world do you pitch that to your fellow board members?