Promising newbies such high a reward is just plain lunatic and very wrong.
Who's promising anything? There are probabilities with everything, and if there is a certain level of increased adoption, then prices rise. There's a lot of ways to get there and a lot of potential obstacles along the way, and whether you are a newbie or not, you have to take information (especially that presented in online forums) with a grain of salt and ultimately come to your own conclusion about what is reasonable or not.
$7,700 is less than a 20x increase from today's prices, which as calculated a $163 billion-ish market cap.... Gold has a $6 trillion market cap, which even with a $7,700 projection for bitcoins would still be 40x larger than bitcoin.... And, a lot of reasonable analysis have already assessed a lot of bitcoin potentials that are quite more functional than gold.... so for example, there a are a lot of real world major contracts that get executed that require liquidity... let's say purchasing some kind of a multi-million dollar asset - a ship full of oil, or a large piece of property. Easier to transfer the value in bitcoin than gold, and there may be reasons that the person prefers not to use traditional banking (or wants to save on banking fees). When bitcoin has a larger market cap, it becomes much more feasible to transfer greater amounts of value without affecting price slippage... and in that regard a larger market cap becomes more useful... and reasonably expected to occur at some point in the near future, whether that be within a year or within possibly 10 years.