At first look this does not look like FUD, but the FUD is implicit in it. For example, let's say that you are interested in running Linux because you want to set up a nameserver running Bind 8, which has many features to improve performance, scalability, and security. You have looked at the name server that came with NT 4.0 but it does not do what you need for your large wide-area network. A Microsoft salesman may then tell you, ``Hold off on that, because the DNS server in NT 5.0 is going to blow BIND 8 into the weeds.'' The goal is to delay introduction of superior technologies so that an industry leader with inferior technology can copy and enhance those superior technologies. The implicit FUD is that if you go with BIND 8, you are going with an evolutionary dead-end that will be obsolete by the time you deploy it.
The danger in promises of future bliss is that it may dry up your current sales while people wait for the promised future. This effect is known as the ``Osborne Effect'', after a computer company named after/by Adam Osborne. The company was the industry leader in ``portable'' (luggable) computers that weighed about 40 pounds but would (mostly) fit under an airline seat, something rather revolutionary in the days before LCD screens. Companies named Kaypro and Compaq made a slightly larger/heavier product that, however, had a bigger screen. Not to be outdone, Adam said ``Don't buy one of theirs, I'll have one with a bigger screen Real Soon Now''. The effect was to dry up Osborne's cash flow, meaning that he did not have the money to produce the Promised Future Bliss. Thus the Promise of Future Bliss is primarily applied in areas where sales are already lost, where you do not have a competitive product and are trying to delay adoption of the competitor's product until your engineers can copy and enhance that product.
An example of the FUD factor involved in ``Promises of Future Bliss'' is how Microsoft handles challenges to NT 4.0. Microsoft primarily uses this technique combined with promises of easy migration from current versions of Microsoft software to the new Promised Future Bliss version. The implication is that if you go with the superior technology (e.g. BIND 8), this will cause problems in the future when you migrate to the ``industry standard'' technology (NT 5.0 a.k.a. Windows 2000). Thus the FUD factor, and also why it is not as succeptible to the ``Osborne Effect''. The hope is that you will buy the inferior technology (the default nameserver under NT 4.0) because you need a nameserver today, PLUS in the future you will buy the upgrade to NT 5.0 to get the promised future bliss, thus buying one product for the price of two.