ES350 engine - don't touch me!

I recently had the opportunity to attend the introduction of ES 350 in
one of the local Lexus dealer. One of the interesting thing about the
new Lexus engines (perhaps applicable to all of the new Lexus car, and
even on other new prestigious cars), is that they seem to "shout":
don't touch me! Notice that almost 100% of the engine is sealed. I
don't see much part of the engine in which you can tamper or "play"
with. It is just a simple, clean "black" box. The only thing that you
can access is the place where to pour in the windshield wiper liquid.
Is this really the intention of the automobile makers nowadays? They
practically say that you do not need to open your car hood, just let
their technicians handle it. I assume that this also happens to other
brand new cars in the market?