If everyone got saved, might as well throw out all the scriptures that pertain to Judgment Day, the book of Revelation,
Daniel 12, etc. And there will be no Millennial Kingdom because that can't happen unless their is a cleansing of some kind. All the teachings about the curse of sin having on humanity would be useless. All the judgments in the past wouldn't be lessons for us to learn.
"The wages of sin is death" is a primary theme throughout the Bible that resonates and warns us of its consequences. What, shall we think there are no consequences to sin? Actually, the Good News would have somewhat of a different message if that were so: "Everyone rejoice, ya'll are goin to heaven no matter what you believe, whatever path, religion, philosophy, good or bad, even if you don't believe in God, ya'll get it!" Yippie Ki Yo Ki Ya! ... Or hallelujah.
The early Church Father, Origen [c 200 AD], who was a universalist, believed there were consequences for sin, that some might spend ages in hell before finally being saved. Does that sound like something you'ld want to experience, or that there are no consequences for sin?
As for Dan. 12:2...
The context supports the view that both the life & the punishment referred to in v.2 are of finite duration (OLAM), while v.3 speaks of those who will be for OLAM "and further".
2 From those sleeping in the soil of the ground many shall awake, these to eonian life and these to reproach for eonian repulsion." 3 The intelligent shall warn as the warning of the atmosphere, and those justifying many are as the stars for the eon and further." (Dan.12:2-3, CLV)
The Hebrew word for eonian (v.2) & eon (v.3) above is OLAM which is used of limited durations in the OT. In verse 3 of Dan. 12 are the words "OLAM and further" showing an example of its finite duration in the very next words after Dan. 12:2. Thus, in context, the OLAM occurences in v.2 should both be understood as being of finite duration.
The early church accepted the following Greek OT translation of the Hebrew OT of Dan. 12:3:
καὶ οἱ συνιέντες ἐκλάμψουσιν ὡς ἡ λαμπρότης τοῦ στερεώματος καὶ ἀπὸ τῶν δικαίων τῶν πολλῶν ὡς οἱ ἀστέρες εἰς τοὺς αἰῶνας καὶ ἔτι[and further]
Notice the words at the end saying KAI ETI, meaning "and further" or "and still" or "and yet" & other synonyms.
eti: "still, yet...Definition: (a) of time: still, yet, even now, (b) of degree: even, further, more, in addition." Strong's Greek: 2089. ἔτι (eti) -- still, yet
εἰς τοὺς αἰῶνας καὶ ἔτι means "into the ages and further" as a translation of the Hebrew L'OLAM WA ED[5703, AD]
So this early church Greek translation of the Hebrew Scriptures agrees with the above translation (& those below) using the words "and further" & similarly.
3 and·the·ones-being-intelligent they-shall- warn as·warning-of the·atmosphere
and·ones-leading-to-righteousness-of the·many-ones as·the·stars for·eon and·futurity (Dan. 12:3, Hebrew-English Interlinear)
http://www.scripture4all.org/OnlineInterlinear/OTpdf/dan12.pdf
2 and, many of the sleepers in the dusty ground, shall awake,—these, [shall be] to age-abiding life, but, those, to reproach, and age-abiding abhorrence;
3 and, they who make wise, shall shine like the shining of the expanse,—and, they who bring the many to righteousness, like the stars to times age-abiding and beyond. (Dan. 12:2-3, Rotherham)
2 And the multitude of those sleeping in the dust of the ground do awake, some to life age-during, and some to reproaches—to abhorrence age-during.
3 And those teaching do shine as the brightness of the expanse, and those justifying the multitude as stars to the age and for ever*. (Dan. 12:2-3, YLT)
* for "for ever" Young of YLT says substitute "age during" everywhere in Scripture:
http://heraldmag.org/olb/Contents/bibles/ylt.pdf
Dan. 12:2-3 was the only Biblical reference to "life eonian" Jesus listeners had to understand His meaning in Jn. 3:16 & elsewhere.
Verse 3 speaks of those bringing "many" to righteousness. The "many" of verse 2, i.e. universal salvation.
https://www.tentmaker.org/books/hope_beyond_hell.pdf