Not everything that's published on Forbes or any news media articles, you should trust them quickly. The Defi's are on the peak hype and they are pushing to the extent that they want to gain more investors and this is just part of the marketing.
Anyway, your link is broken.
In recent time the prices of Defi coins has being on rise and rising very quickly. I am sure considering this many would be tempted to invest in it to become part of the rising prices and make some profits from it. But yes as you said can it be a part of marketing and in the end prices falls drastically from the top this is uncertain.
Yes, they are all rising quickly. Look at the different projects that were inspired by yearn.finance. They have labeled their name with the same name but just like the forks, they've added name to the original name so that investors will notice it.
And they can think that it's also the same as the original defi that can also go up.