I dont think you should mention Unity as a good business model, they are in big trouble.
I used to think the same way about subscribing to Construct, but have changed my mind a lot over the years. We all want the best value for money we can get.
Somehow we are all allergic to pay for software.
But you go to watch a 2 hour film at the cinema and it cost around £10+ now, swimming or sports hall session is the same.
For a hobby paying yearly works out to £8.66 per month at the current price.
I looked at Gdevelop as a mainly free similar alternative but decided to renew C3 another year. Gdevelop has some features over Construct i like, but found you never know if or when a bug will get fixed and they seem to be moving more to a tiered subscription model themselves.
Lastly if i'm reading Scirra's tax statements correctly they continue to increase their profits each year, so i doubt they will be motivated to change from a subcription model.