Consumer speakers are meant to sound beautiful. What beautiful is,.. is in the eye of the designer. But, you won't sell a lot of your speakers if somebodies test cd is shrill and boomy in some environments so a lot of attention is paid to making it sound reasonably good at the extremes regardless of the room treatment.
Studio near/mid field monitors are not designed to sound good. They are designed as tools for tracking and mixing (not mastering!). They can be accurate to a fault.
Just an example,
Most folks hate sibilance. But reducing sibilance can roll off highs and make the recording sound dull.
Finding the right balance is the mixer's job. To do a good job of it, he's got to hear that irritating stuff clearly.
Regarding the lack of bass, if you're reading review of monitors on pro audio sites, everyone there knows that you can't expect most nearfields to go down much below 50Hz. But, they also know that there isn't a whole lot below there on most recordings. So once they've gotten the bass and the kick (organ if it's there) to play nice with each other, everything else is well above 50.
All mixers have some way to check those lower frequencies though (headphones, switchable sub etc).
The bottom line for monitors for mixing and tracking is, since no monitor/setup is perfect, you need to know that system. What does it lack and what freq bumps does it have.
That said, all the above does not mean that the monitors can't sound great for casual listening, it just means that when you read a review over on Gearslutz or Sound on Sound, "great" may have a very different meaning that what you might think.
Monitors for mastering are a whole different thing. They need to be full range and often have subs.
They are never nearfields and can extend far beyond midfield.
They are often some very high priced audiophile speakers with room acoustics and amplification as perfect as possible. How much $$$ is spent in this pursuit depends on their target audience.
Almost all mastering rooms are set up by master acousticians.
And even though these guys usually have the best ears in the business, learning the sound of their room is critical.