The legal and
de jure line of the Kings were always in Matthew's genealogy, but due to the curse, the Lord in the meantime selected Zedekiah's line (via his daughters) to go to the Zarahite line as you well know. These are king
de facto.
Ezekiel 17:22-24:
Thus saith the Lord GOD; I will also take of the highest branch of the high cedar [this is Zedekiah's family line], and will set it; I will crop off from the top of his young twigs a tender one [tender is feminine, thus a daugher, not Messiah, who is not even of this genealogical lineage], and will plant it upon an high mountain and eminent:
In the mountain of the height of Israel [i.e a mountain represents a nation, where the lost house of Israel resides] will I plant it: and it shall bring forth boughs, and bear fruit, and be a goodly cedar: and under it shall dwell all fowl of every wing; in the shadow of the branches thereof shall they dwell.
And all the trees of the field shall know that I the LORD have brought down the high tree, have exalted the low tree, have dried up the green tree, and have made the dry tree to flourish: I the LORD have spoken and have done it.
Why?
Because of the curse of Jehoiachin where the Lord said in Ezekiel 21:25-27 (although this was stated to Zedekiah):
And thou, profane wicked prince of Israel, whose day is come, when iniquity shall have an end,
Thus saith the Lord GOD; Remove the diadem, and take off the crown: this shall not be the same: exalt him that is low, and abase him that is high. [i.e. the low lineage is of Zarah, and the high is Pharez, the same concept of the green tree and dry tree in the previous scripture]
I will overturn, overturn, overturn, it: and it shall be no more, until he come whose right it is; and I will give it him.
This made a "breach" in the Pharez lineage where kings no longer rule in Judah. Modern Christendom rightly sees this breach and assumes there are no more Kings until Jesus repairs that breach and reestablishes the throne again. In a sense, they are correct that there is no more Kings, but that is in the land of Israel only --- they fail to look outside of Israel.
Why the breach? And why move the throne to Zarah even if they were in the isles? What makes them so special?
It was prophesied by a midwife no less in Genesis 38:
And it came to pass in the time of her travail, that, behold, twins were in her womb.
And it came to pass, when she travailed, that the one put out his hand: and the midwife took and bound upon his hand a scarlet thread, saying, This came out first.
And it came to pass, as he drew back his hand, that, behold, his brother came out: and she said, How hast thou broken forth? this breach be upon thee: therefore his name was called Pharez.
And afterward came out his brother, that had the scarlet thread upon his hand: and his name was called Zarah.
That mention of a scarlet thread was not for a scribe's exercise to mention, but was significant of something to occur in the future although overlooked by most. That thread signified royalty in some way.
So we can see that once the curse was uttered, God chosen Zedekiah's lineage via his daughters to be conjoined to Zarah in the isles. The Law allows the daughter's Judaic inheritance in King David to be perpetuated as long as they married in their same tribe:
See Numbers 36
And why perpetuate the throne de facto?
Because God said to King David in 2 Samuel 7:16:
And thine house and thy kingdom shall be established for ever before thee: thy throne shall be established for ever.
In the meantime, due to the de facto reign, why don't the throne just stay there? What's the purpose of it going back to Matthew's genealogy?
Again, the passage in Ezekiel answers this:
I will overturn, overturn, overturn, it: and it shall be no more, until he come whose right it is; and I will give it him.
Which shows that Matthew's genealogy, although cursed is the RIGHTFUL lineage. In a nutshell, God just put that lineage on "hold" and selected another, until it was time to take it off hold again, and the curse was the means to keep it on hold.
I don't tell people this on forums usually, but I have a web site with BI type beliefs. I even deal with the curse of Jehoiachin more than most BI sites do, as I know the Lord dealt that with me and made me to understand the significance. One famous BI site in Canada actually links to my site, and that pastor asked me to pair up with him and put stuff out together over the web. I graciously declined being flattered, but it indicated to me that I understood genealogically speaking the reason that the royal lineages went the way they do.
Don't ask me for the name of the site because I won't give it, but I'll leave this tantalizing genealogy suitable for framing:
http://1.bp.blogspot...600-h/GQEII.jpg