Re: your last explanation line:
"I just don't understand why Jews did not convert to Christianism [sic] since the Messianic prophecies are known by everyone, they were not hidden"
The fact is, Jesus failed to fulfill an actually *messianic* prophecy. It is also clear that not "everyone" knows the actually messianic prophecies, since so many Christians make that mistake.
The writers of the Christian scriptures retooled the Tanakh (Hebrew Scriptures) into the "Old Testament" and made it look as if Jesus was the one foretold. Since he failed to fulfill the messianic prophecies, we know that he was not. The Jews are waiting for the man who fulfills all of the messianic prophecies during his lifetime.
First of all, you have to know what the "Jewish prophecies" are in regards to "messianic prophecies".
1. Descendant of David - (Jeremiah 23:5) (there are more regarding this one), note, must also be a descendant of Solomon (1 Chronicles 22:9), but can not be a descendant of Jeconiah (Jeremiah 22:30 This is established only through the biological father (for line/tribe) Numbers 36 (Tribal lineage), Genesis 49:10, 1 Kings, 11:4, 1 Chronicles 17:11-19 (Kingship lineage), Exodus 28:4, 29:9-30, 30:30, and 40:15 (Priesthood lineage)
2. Preceded by Elijah - Malachi 3:23-24
3. World Peace - Isaiah 2:4, Ezekiel 39:9
4. Universal Knowledge of G-d - Isaiah 11:9, Jeremiah 31:33, Zechariah 8:23, 14:9, 14:16
5. Building of the Third Temple - Ezekiel 37:26-28 (See also Ezekiel 40-48, Isaiah 33:20)
6. Death Will Cease - Isaiah 25:8
7. Resurrection of the Dead - Isaiah 26:19, Daniel 12:2, Ezekiel 37:12-13
8. Ingathering of Israel - Isaiah 43:5-6 (See also Jeremiah 19:15, 23:3, Isaiah 11:12, Zechariah 10:6, Ezekiel 37:21-22)
9. The Nations Will Help the Jews Materially - Isaiah 60:5, 60:10-12, 61:6
10. Eternal Joy and Gladness Will Characterize the Jewish Nation - Isaiah 51:11
11. The Jews Will Be Sought For Spiritual Guidance - Zechariah 8:23
12. All Weapons Of War Will Be Destroyed - Ezekiel 39:9
13. The Enemy Dead Will Be Buried - Ezekiel 39:12
14. The Egyptian River Will Run Dry - Isaiah 11:15
15. Trees Will Yield New Fruit Monthly in Israel - Ezekiel 47:12
16. Each Tribe of Israel Will Receive It's Inheritance - Ezekiel 47:13-14
17. All Warfare Will Cease - Isaiah 2:4
Also, we know that the messiah will be an actual king, ruling in Israel, and sitting on the actual throne in Jerusalem. And that there will be no dispute as to whether or not this Jewish male is the messiah or not. (Jeremiah 23:5-6, and Isaiah 42:1-4)
To quote a friend, "When we carefully consider that none of this has occurred, we can be assured that although many thousands of individuals have claimed to be the messiah throughout the centuries, Jesus included, none of them is. Moreover, when we ponder whether Jesus is the messiah, it is obvious that the very opposite occurred immediately after the Christian movement began; that is; During the first century the Romans slaughtered many thousands of Jews, the Jewish people were exiled from their land, the Temple in Jerusalem was destroyed, the knowledge of Torah and its observance decreased throughout the Roman Empire. Clearly, there is no relationship between what the Hebrew Scriptures say about the messiah and what Christianity teaches about Jesus."