Are Scribal Additions Hiding Variant Textual Readings in the New Testament?

I really think I am on to something with this idea that scribes 'corrected' what we might call 'Marcionite' readings (meaning 'shortened' versions of existing canonical references) by adding a few words to make it seem the beginning and end of a section were meant rather than it being a variant reading of a shorter (= Marcionite) canon.  I don't know if anyone has ever suggested this before.  Of course not everyone of these references is going to represent such a scribal addition.  Nevertheless I would venture to guess that this happened more than is currently acknowledged.

Eusebius Commentary on Luke 24.577 Πρὸς τοῦτον οὖν φησιν· Ἄνθρωπός τις ἐποίησε δεῖπνον μέγα, καὶ τὰ ἑξῆς. Ἤρξαντο ἀπὸ μιᾶς παραιτεῖσθαι πάντες.

ἄνθρωπος τις ἐποίει δεῖπνον μέγα, καὶ ἐκάλεσεν πολλοὺς καὶ ἀπέστειλεν τὸν δοῦλον αὐτοῦ τῇ ὥρᾳ τοῦ δείπνου εἰπεῖν τοῖς κεκλημένοις· ἔρχεσθε ὅτι ἤδη ἕτοιμα ἐστιν. 18καὶ ἤρξαντο ἀπὸ μιᾶς πάντες παραιτεῖσθαι.

(Jesus replied) “A certain man was preparing a great banquet and invited many guests.  At the time of the banquet he sent his servant to tell those who had been invited, ‘Come, for everything is now ready.’ But they all alike began to make excuses."

Origen Commentary on Matthew 10:11 «Ἐν δὲ τῷ ἀποστρέψαι δίκαιον ἐκ τῆς δικαιοσύνης αὐτοῦ καὶ ποιῆσαι ἀδικίαν» καὶ τὰ ἑξῆς ἕως τοῦ «καὶ ἐν ταῖς ἁμαρτίαις αὐτοῦ αἷς ἥμαρτεν, ἐν αὐταῖς ἀποθανεῖται»

And Isaiah is reported to have been sawn asunder by the people; and if any one does not accept the statement because of its being found in the Apocryphal Isaiah, let him believe what is written thus in the Epistle to the Hebrews, They were stoned, they were sawn asunder, they were tempted; Hebrews 11:37 for the expression, They were sawn asunder, refers to Isaiah, just as the words, They were slain with the sword, refer to Zacharias, who was slain between the sanctuary and the altar, as the Saviour taught, bearing testimony, as I think, to a Scripture, though not extant in the common and widely circulated books, but perhaps in apocryphal books. And they, too, were dishonoured in their own country among the Jews who went about in sheep-skins, in goat-skins, being destitute, afflicted, and so on For all that will to live godly in Christ Jesus shall suffer persecution.