They did; that was the "large influx of cash" part of the post you replied to. But unless you want your software to be released once and not have continued development after that, "build it until it's perfect, then release it, then retire" doesn't make much sense.
I do subscription models for a few select apps that I feel are worth it; including one in this bundle. Other times, if a developer offers a subscription OR a permanent license, I'll get the permanent license. Panic Transmit is that way; you can buy annual licenses, or you can buy version 5 at a set price and be done with it, but not get "the next version". I, like some others here, remember bundles like these having actual permanent licenses tied to specific versions of software; this seems like it would be nice if you need parallels and want to try some of the other apps, but in general, a bundle of subscription apps is very underwhelming.