Just like with anything else, exit route is a function of time and budget and the migration cost is always proportional to the previous customization effort. If

Just like with anything else, exit route is a function of time and budget and the migration cost is always proportional to the previous customization effort. If you pay 100k per year in license costs and spent 200-300k in 2-3 years to build current setup, you may need another 0.5-1M to get off this hook and jump to another one (which will be hard to pick). I doubt anyone seriously considers this scenario, because risks are too low and rewards are too high (it is a really good product, for which in many scenarios it is hard to find cost-efficient alternative).