The scene mirrors not so much Tony's paranoia, but his need to be paranoid. He can't live comfortably, he can't afford to. All this wealth and prosperity has brought him to a miserable, wretched life, with only surface grins and warmth.
In addition, I think a lot of Tony's paranoia was based on the decisions that his children were making, as I would describe Carm and Tony as
content with the way the children were turning out, and not happy. They were content, because things could have been infinitely worse after the NY/NJ war and AJ's contrived attempt at suicide. But in fact, their worst fears were coming true with their children as Meadow was looking to marry the son of one of Tony's associates. Are we to believe that she and Jason Parisi were truly going to become civil rights attorneys, or would they turn their legal efforts to helping 'the family'?
But it was AJ's path that was turning the most ominous. After a
shallow attempt at suicide, he does a complete 180 (per usual) and decides to join the army. But then, after Tony AND Carmela present a bogus job in the 'film' industry with Carmine Jr., and talk of Tony investing in a future night club, AJ completely drops the Army idea in a split second. In his last scene, before the final supper, when he goes to pick up his girlfriend from school in his new BMW, notice the absence of color in that scene--it has a very 1920's German Expressionism eerieness to it--I think it's synonymous with AJ and his new nihlist pal, who are completely devoid of any real emotion or life at that point. Life really means nothing to AJ b/c he has been given everything by his father (the new car, after the previous one caught fire), which is precisely what Tony told Melfi many times that he didn't want for his son. At the last supper, AJ tells Tony and Carm how much of a phony, artificial job he has with Carmine, Jr. to which Carmela replies, in her typical suburban-mom rhetoric, "You may not know this, young man, but you are gaining valuabe contacts" to which AJ casually shrugs off and quips with his now infamous "Remember the good times, right?" A tell-tale sign that the times at hand were not so good. AJ certainly wouldn't have been able to escape the mafia life if he spent his career operating a night club financed by 'waste management' funds.
Of course, I think Tony's death would have changed all of that. Meadow would have dropped Jason; AJ loses his bogus job with Carmine Jr., and upon his father's death, finally gains a meaning and understanding of life that Tony desperately wanted him to find.
...Thoughts?
