Data export is not a problem until you decide to migrate away, then it will be too late. When you need it you may discover that data export is really really poor and you can’t migrate all of the dataset but just part of them.
Why? Let’s imagine, for instance your old CRM is not producing an export of the table properly linked to other tables. That data will be totally useless when imported into another Customer Relationship Management, as there is no way to relate them to other data.