Why there is no מלכות in the first ברכה of Shmoneh Esrei

Bereishit 24:3:
וְאַשְׁבִּיעֲךָ--בַּה' אֱלֹקֵי הַשָּׁמַיִם, וֵאלֹקֵי הָאָרֶץ: אֲשֶׁר לֹא-תִקַּח אִשָּׁה, לִבְנִי, מִבְּנוֹת הַכְּנַעֲנִי, אֲשֶׁר אָנֹכִי יוֹשֵׁב בְּקִרְבּוֹ.
"And I will make thee swear by the LORD, the God of heaven and the God of the earth, that thou shalt not take a wife for my son of the daughters of the Canaanites, among whom I dwell."

Here, Abraham makes Eliezer swear by אֱלֹקֵי הַשָּׁמַיִם, וֵאלֹקֵי הָאָרֶץ.

However, later, when reassuring Eliezer/praying for success in his mission (see Ibn Ezra who proves it was tefilla and not nevua), Avraham says:
Bereishit 24:7:
ה אֱלֹקֵי הַשָּׁמַיִם, אֲשֶׁר לְקָחַנִי מִבֵּית אָבִי וּמֵאֶרֶץ מוֹלַדְתִּי, וַאֲשֶׁר דִּבֶּר-לִי וַאֲשֶׁר נִשְׁבַּע-לִי לֵאמֹר, לְזַרְעֲךָ אֶתֵּן אֶת-הָאָרֶץ הַזֹּאת--הוּא, יִשְׁלַח מַלְאָכוֹ לְפָנֶיךָ, וְלָקַחְתָּ אִשָּׁה לִבְנִי, מִשָּׁם.
"The LORD, the God of heaven, who took me from my father's house, and from the land of my nativity, and who spoke unto me, and who swore unto me, saying: Unto thy seed will I give this land; He will send His angel before thee, and thou shalt take a wife for my son from thence."

Here Avraham only mentions אֱלֹקֵי הַשָּׁמַיִם.

Rashi explains this was because at the time Avraham was told to leave, Hashem was not yet
אלֹקֵי הָאָרֶץ and that is why that appelation is not mentioned here although it was above in pasuk ג.

Daat Zekeinim MiBaalei HaTosafot on the basis of this explain why there is no מלכות in the first ברכה of Shmoneh Esrei. Usually brachot begin "Baruch Ata Hashem Elokeinu Melech HaOlam," and this is the only bracha in Shmoneh Esrei that begins Baruch Ata Hashem (the others do not begin with a bracha). Since Hashem's malchut was not accepted throughout the world (מלך העולם) at that time, we do not say the formulaic מלך העולם.