Marketers do not "lie"; engineers just "cannot do their jobs". I have worked several jobs where everyone had "done their job", made the company money, and all we engineers had to do is just deliver the product before we leave for the day. Most times engineering has always been the bottleneck when creating that new little feature that was needed to sell the product. Joke example: a nuclear submarine company's engineers could not make their hatches fully compatible with the International Space Station's air locks and then keep making excuses about not being able to do a full scale onsite test at the ISS to show the customer this little feature that clinched the sale >;-). You have not enjoyed engineering until you have a meeting (with sales, marketing, and management) and finally find out what the product really does just before it ships.
Mushware while defining a product is one thing, Mushware while promoting a product is something the developers cannot do anything with.
For example way back in 1990s , we developed an interactive TV with a bulit in co-processor having the capability of storing small BASIC programs. This was basically aimed at school going kids to learn programming techniques with simple programs.
Our marketing team hyped this feature to such an extent that they sold one of ourr TVs as an Accounting system to one shop keeper, telling him that he can program his TV to store all accounts for his business.
We had a very hard time in answering the after sales querries of this shop keeper on how many accounting entries his TV could store and so on and how can a printer be attached to the TV to print his account books!