As usual, your questions are few in words and full of meaning.
Like with all the Prophets, their language is usually not to be taken in a literal sense, but rather in an allegorical sense.
In this case, the stone mentioned is referring to a particular King destined to lead the nation of Israel. This is in keeping with both Targum Yonatan and Radak to this ...
The full quote from the Ritva is very interesting, but also makes your question a non question.
תשעה נטלו חזירים. יש שפירשו עמלק כדכתיב בו יכרסמנה חזיר מיער ועליהם אמרו בהגדה למה נקרא שמו חזיר שעתיד הקב"ה להחזירו לישראל לעתיד לבוא. ואין צורך לכך כי בספר הטבעים כתב שהצרעת ונגעים בחזירים הרבה בטבע:
Regarding the 9 out of ten measures of tzaraas in the ...
"Those who prepare themselves and purify themselves to the gardens,
[one] after another in the middle, those who eat the flesh of the
swine and the detestable thing and the rodent, shall perish together,"
says the Lord.
Speaks of those who deliberately flout the halachos of the Torah, such as eating חזיר, before the mashiach comes. ...
In the time to Come the Holy One, blessed be He, will announce "Anyone who didn’t eat pig’s flesh may come and collect his reward." It is difficult – why announce about a negative mitzvah of eating, any more than the rest of the negative mitzvahs of other forbidden activities which do not pertain to eating. Further, why make such an announcement about pig, ...
The Ohr ha-Chaim [on Lev. 11:7] says that in the Messianic Age God will change the pig's anatomy so that it chews its cud, and thereby become kosher.
What Isaiah said will happen first. At a later time the pig will become kosher.