Other than the basic math issues involved (most third graders don't have the finger reach to play a regular Boehm clarinet), the only message that I would want anyone to take away from all of this is that a Noblet clarinet is (if well maintained) a good enough instrument for anyone, pro or amateur. It's a better horn than most of the intermediates, and I've known any number of pros who play them. (Not me, though - for me it's Selmer Series 9 or nothing at all.)
(For the record, I play a little soprano clarinet these days (mostly shows with a very little community orchestra work), somewhat more bass clarinet (shows and sub work with orchestras paid and unpaid), and a lot more baritone and alto saxophone (with my group). I put in about ten hours a week, both performance and practice (very little of that). I've got an A clarinet that accompanies my Bb soprano everywhere, but seldom comes out of the case.)
To improve the quality of anyone's clarinet experience, the closer you get to the north end of the mouthpiece, the greater the influence. There is a strong tendency to look at the horn as the thing to work on to improve one's clarinet playing. This was, and is, the wrong way to go about it. It's also the most expensive.
In general terms, the barrel has more influence on the playing than a well maintained horn, the mouthpiece more than the barrel, the reed and ligature more than the mouthpiece, and the next item in line (the player) more than any of the others. Sure, it's a generalization, and sure, a flaw anywhere along the line can bring the whole affair down in ruins.
However, practice (and, for those who have the time and money, lessons) will make more of a difference than any of the others. They both are cheaper than new reeds, new mouthpieces, new barrels and new clarinets (assuming all of these are in good repair).
I've encountered professional sax players who were wizards on the clarinet as well, but who had (being saxophone players) never bothered to truly learn the instrument. Not knowing about "one and one" had hampered them for years - something that you pick up on in perhaps the tenth lesson that you take. And, someone who's been away for a long time may have dropped a few of these tricks over the years.
Some community groups, particularly concert band type groups, are pretty forgiving of someone who comes on board with minimal skills. I have encountered such groups over the years, and while they aren't up to "pro" standards, they serve as a useful outlet for the player who doesn't have time for practice.
However, most of my acquaintance are a bit more "demanding" of the horn players than a "come as you are" concert band. Groups like the Compton Heights Concert Band (up in Saint Louis, has been around for many years) would show you to the door if you came in unprepared.
The community orchestras around Houston are that way as well - with limited seats for clarinet players, they are very selective about who they let occupy them. It may be different in your neck of the woods, but the phrase "Practice makes perfect" certainly applies in these cases. In the two that actually pay money, you would be expected to handle both A and Bb parts (or bass parts), and to have the transposition skills to deal with the periods performed, when you first sat down to play.
What about the "professional musician", a term that gets abused a lot? Well, iffen you get paid, then you are a pro (at least in the eyes of the IRS, an excellent benchmark for judging such things). Most folks who make some money at music do it part-time, as it's unrealistic to play professionally (for most folks) and still have a decent standard of living. (I'm retired, after just under forty years with the government.)
While none of the guys and girls that I use are Morales-level players on clarinet, all have the skills necessary to handle the charts that we play that have clarinet parts. (All are very proficient on sax - I've also got a doctor of clarinet performance in the group when he can make a job. I've even had one guy who played a Noblet plateau clarinet, and I paid him just the same as the others.) And, that's what we have to expect when we get paid good money by clients who want value for money paid.
Push comes to shove, there are all sorts of points on the wide spectrum of clarinet playing, and (most importantly) anyone playing a well set up Noblet soprano horn can occupy any of them. There's no need to invest in the ubiquitous R-13 for any of these situations, much less for casual playing. And, almost anyone would benefit from a few lessons (if they can afford them, both in time and treasure) if they have been away for more than a few years.