That's certainly true, but if I wanted to pay for my sub upfront and at a cheaper rate, I would do so by paying annually not monthly which achieves the same result.
Frankly I don't have that amount of money lying around, but it is evident that what we are paying for here is really the subscription and not the software - hence the different packages for different subscription levels. It is in effect the software that is "free" and being bundled in with a subscription deal and not the other way around. There is no difference between the different levels of FTM package other than the attached sub.
Ancestry already has my sub, I am committed to membership and especially as the software is now available as a download I would prefer an option where I can have a surcharge added to my running sub one month to pay for it, rather than paying up front for six months membership.
Clearly they are making money from new subscribers through this, but I find it decidedly odd that there is no option to purchase the software as a standalone.