@Red Indian Chief Torn Rubber
I think the goalposts have shifted somewhat.
Your original point wasn't that Xavi/Ineista/Busquets wouldn't have worked in a midfield three, but your point was that specifically it wouldn't have worked
defensively.
I agree that that midfield three would be nowhere near as effective for Spain as it would be for Barcelona but you then changed your argument away from the defensive side to the offensive side. But defensively, without Alonso, it would have been fine. Iniesta would be far less effective however.
Alonso was never put there to provide defensive stability, as was your original point, he was there to provide more accurate passing from deep to the channels in a more congested midfield, something which Spain had a problem with as they never played with any real width in the attackers. Messi solved this problem for Barcelona by being all over the pitch.
Actually, Del Bosque actually tried the Barca way in the 2010 world cup semi final vs Germany. He set up Villa to be a free roaming forward in a false nine fashion, interchanging with Pedro who would also drop deeper and throughout the whole pitch. The idea was to give Iniesta space to both drive forward into the midfield and to loiter in the channels AND the fullbacks to provide the width. Xavi would drive from midfield from deep and Alonso actually played the Xavi role of playmaking from deep. Villa played the Messi role, Pedro played the Villa role at Barcelona and Iniesta bizarrely played the Villa role. This backfired spectacularly resulting in a drab game that should have ended 0-0 in all honesty.
Pedro and Villa both constantly dropped deep, hoping to drag the Germans out of position and to create space. The problem was, when Messi drops to the 35 yard area, he has to be marked because he can conjure up bullshit magic from nowhere. Germans just left Pedro and Villa alone and let them have the ball in that area. What ended up happening was Pedro and Villa got the ball constantly in the deep, neither had the creativity or forward dribbling to really threaten from there and the Germans just let them have the ball.
This is the heat map for Pedro:
This was the heat map for Villa:
As you can see, both these players dropped deep and did nothing. Germany kept their shape and their discipline. Iniesta didn't have the space in the channels to really get behind the defense OR to drive forward with the ball. Xavi driving forward from deep faced the same problem (no space) and Alonso couldn't do the Xavi ticking job as well as Xavi himself could. Spain had shit tonnes of the ball but couldn't do anything with it. With this setup, where Xabi Alonso wasn't even playing defensive midfielder, defensively Spain were fine.
This is where they gave up trying to replicate Barcelona type of football. They just couldn't do it with the players up top that they had at their disposal.
Rice, Foden and Bellingham will work fine. Bellingham can provide the type of offensive and defensive output to assist both up top and in the deep.
Look at France 2018 team, their midfield 3 was Kante, Pogba and Griezmann as number 8. They had Matuidi, yes, but he was utilized as a left winger for some reason.