Comment by HelloNurse

For the customer, automatically converting long subscriptions to perpetual licenses for an old version is a major safety net (the software will not stop working if I stop paying) and it proves that the vendor is committed to improving the product enough to make upgrades compelling.

On the other hand, reasonable customers do not expect support beyond the latest version and whatever they are currently paying for: "we have fixed that in the latest version, which you should buy" is a valid and honest answer to support issues.

For a tool that can be changed with very little friction like a revision control client, the typical "calculation" about spending money is likely to be waiting for an actual troublesome situation and then get out of it with a short subscription or a 30-day trial.