Your answer is spot on, the other aspect of most new world wines is that they are generally grown in hotter climate. (Than France)
In Bordeaux and the Rhone region the sun is definetely softer
grappes mature slowly but properly (In a good vintage)
I do not know too much about Californian wine growing, but both Australian and South African wine making are showing a new trend which I do not agree at all with. They tend to pick the grappes later to get more fruit but unfortunately this also translate to higher alcohol.
Many wines these days have 14% or even 15% alcohol.
They are very forward, rich and fruity but again with little complexity.
Living in South Africa I have seen enormous progress during the last 15 years or so, but although the standard is quite high and they do make good wines. I never tasted a great wine, a classic.
(Thelema cam close on a few occasions)
I also found that in general wine from the new world tend to age, rather than mature. I went through a phase collecting wines but now
I have given up on keeping Australian, Californian, or South African wines, I drink them young, when they are nice.
I still buy good French wines for keeping (in small quantities) and
for special occasions. Like you I love the Rhone wines.
Especially the Cote Rotie such as La Mouline from Guigal,
even a good vintage of Brune et Blonde blows me away, plenty good
wines from Chapoutier and Jaboulet.
While in Belgium last month I went to a tasting from wines from the Languedoc and I must say, I was impressed.
An analogy with audio, wines from the new world are like hi-fi, great wines from France are like the real thing.
Cheers
jazz1