I'll defer to your clear greater knowledge of Brazilian football but I think there is a little overhyping of the 1986 and 1990 teams, neither of which had players on the level of the Pele era or the Romario-Ronaldo era.
But taking what you say on face value, particularly re "Nearly all of Brazils most technically brilliant players gone by were forged in fires that are no longer consistent resources anymore, which is why you’re not just going to get that back and especially not en masse", why aren't you going to get that back? There is still a lot of poverty in Brazil so I can't believe the favela street footballer taps have been turned off.
Is it Europeans have caught up with better coaching? Is it Pep-ball strangling the life out of creatives? I agree that in the times of Ronaldinho, Denilson etc. there were a good amount of entertaining Brazilians. They can't just have disappeared?
I believe, globally, there’s a decline in street football, pick-up games and that kind of off the cuff vagabond spirit. In the past, stories of kids all over the world who were obsessed with football would be sprinkled with tales of waking up with a football, honing technique against walls, in parks/streets/beaches <insert what is appropriate per region> to extraordinary levels. Familiarising oneself with one’s own capabilities and being self-driven enough to go out the next day, and the next, and the next playing in unpredictable environments against unpredictable opponents and constantly finding solutions. Stories of a Best or Charlton, even on this side of the world, perfecting technique, alone obsessively for hours on end; for all the talk of joy and free spirit, when broken down to raw training, what Brazilians used to do in their droves for hours and hours and hours on end, whilst having fun, is bound to create unparalleled levels of technique, and doing it on beaches, on sand too, that’s creating a central core and levels of balance and adaptation that makes a consistent grass surface a cakewalk to traverse.
I think the link between the likes of futsal and impeccable, transferable technique has been discussed on here before, but all these methods that gave Brazilians that famed panache are fading or being replaced with generic academic development and that comes with its own problems, particularly in terms of perception of the game and problem solving; all those aforementioned pickup hours replete with endless amounts of unpredictability forge a different kind of player, in my opinion, and what we used to see, and what gave Brazilians that awe-inspiring ability, was their ability to make generic academic learning look wooden, stiff and easily compromised i.e. humiliating and embarrassing wooden opponents - I don’t think that’s unique to Brazilians - you’ll find links with many insanely talented individuals and the wits and guile streetball or futsal gave them - the marrying of their technical advantages and playing systems that allowed them to display their superiority is what gave Brazil their edge. By the time you put that honed ability to a cultured style of play, it used to be very, very difficult for opponents to stop.
Fast forward to now and the kids are not forged in those fires and no longer have a clear technical advantage over their peers (the last real magician Brazil produced is Neymar, I think many old ways are fading around the world and what gave us those great technicians won’t be returning; it isn’t just about poverty; plenty of areas around the world have had that ‘play from dusk til dawn’ spirit erased or eroded and Brazil have to be far from immune from that.
Europe never had better coaching, but they had their own coaching methods bespoke to their players, technical levels, characteristics and physical capabilities, just as Brazil used to (and Argentina still does to a greater extent), and it was about harmonising their players traits and abilities with tactics and systems that got the best out of them without curtailing expression. The attempts to conform to football styles that have little to do with their playing origins is mostly going to be ruinous. Think of it in reverse; getting an England, Germany, Italy or Spain to be as wildly exuberant as the defined versions of jogo bonito. It would be equally daft and working away from the core strength of those nations. As I said in a previous post, the only way that kind of thing can work is by Brazil mimicking Europe to the wire, from childhood straight through, which should go against everything Brazil have been known to stand for until the 2010’s when they’ve really lost their way to the point threads like this can be created.