Its hard for me to imagine ever selling an app for a lump sum single payment. Software development is an iterative process and there needs to be a payment system reflecting that.
But for the runaway success of the iPhone App Store model software-sold-like-shirts would probably be in even wider retreat than it already is. (The competitive models include "$X upfront plus 20% yearly for maintenance", "$X upfront plus an upgrade cycle which strongly encourages you buy a new version for 50% of X every 18 ~ 24 months", and, of course, SaaS. The popularization of the SaaS billing model is one of the biggest things that happened for software in decades, because it lets you sell $4,000 software to someone with $200 of willingness/capability to spend.)
When the path to profitability is to improve the software so users choose to upgrade, the interests of the users and the developers are aligned; better software is good for everyone.
With subscriptions, users keep paying whether the company improves the software or not - so the less the company spends on development, the more is left over to take as profit.
As a developer, I think the traditional sale option sounds much healthier for the industry, and hence much better for me.
Edit: I interpreted the comment I was responding to as lump sum vs ongoing subscription, rather than paid vs free upgrades. In that light, perhaps the parent poster and I actually agree!