The migration nobody wants to do
The old system everyone complains about but no one replaces is usually costing more than the scary migration would. Avoidance has a price.
Every organization has one: the aging system everyone agrees is bad, that nobody will touch because migrating off it feels terrifying. So it lingers, accruing cost and risk, protected by the fear of the project to replace it.
The status quo has a cost too
Avoidance feels free because the cost is spread out — the daily workarounds, the things you can't do, the risk of the thing finally failing. Compare that honest, ongoing cost to the one-time migration, and the math often favors moving sooner than the fear suggests.
Migrate in slices
The terror comes from imagining a big-bang cutover. It rarely has to be that. Most migrations can move one piece at a time, running old and new in parallel, shrinking risk at each step. The scary project becomes a series of manageable ones — which is also how you actually get it done.
The migration you keep avoiding is usually cheaper than the system you keep tolerating. Count both costs honestly.