I prefer the subscription model, as long as the total expected cost is not too far out of line for the service. $5/mo for every tiny utility is too much.

However, before the rise of subscriptions developers still needed income. What often happened were releases with big changes (sometimes completely changing the ui) for the sake of justifying an upgrade cost. Even worse, incompatibility between versions to force an upgrade.

Perpetual license of an older version included with the subscription does seem like a good middle ground here.