JAS said

If Marcion did not write anything, how did he show this way? Why should we care what Marcion might have thought? How would we know what he thought?

Unfortunately I missed this JAS comment for which I apologize.
JAS’s comment clearly indicates that I cannot find the right argument for Marion’s reconstruction.
So another version.
Various Christian sects clash in Rome. They fight for the most important territory in the Empire in terms of politics, finances and population density. In Rome, the fate of various religions of the Empire was decided: here it was decided about official persecution, here it was decided to admit the cult to religious activities, here the cults which reached a certain critical mass and acted in the interests of the Empire were promoted. These historical stages are common to  Serapis, Dionysus, Isis,… Permanent practice of the administration of the Empire – persecution, admission to public activity, elevation and joint – promotion. Of course, for those who have achieved market success.
Various Christians attack Rome at an early stage, when religion is secretly professed and there are already problems with market competition. First of all, they all sell Jesus, but in different versions, the seriousness of the product and the sellers suffers. And a compromise is needed on how to share this Rome.
Various leaders go to Rome and conduct several years of product and management negotiations. There is also the ascetic Marcion, who throws 200,000 sesterces of the Roman commune as an incentive.
What do the gathered decide? About collective management, about the method of counting the authorized votes, about common theology.
No one is excluded for theological views, and Valentinus is even a candidate for Bishop of Rome. Loses. He becomes a heretic. Marcion, after a few years of playing as part of this society, also sees that he will not achieve the intended goals and leaves. And he also becomes a heretic but level MaxTurbo. Why? Because his organization has achieved a positive EBITDA, is financially independent and can independently carry out costly but effective missionary action. In their criticism, Marcion’s opponents resort to the methods adopted by the NKVD in the Stalinist trials. Independent and effective, Marcion is a deadly threat to them.