Benedikt, you have misread St. Thomas. Here is what he said (https://aquinas.cc/la/en/~ST.III.Q72.A2):
The objection states that olive oil can be replaced with any type of oil as matter of the Sacrament:
In his response, St. Thomas explains why that opinion (Obj. 3) is wrong:
The red underlined part above is what you are misinterpreting. The Latin is clear: "nisi in supplementum apud eos quibus deest oleum olivarum" [except to supplement in case of a shortage of olive oil].
but the olive oil must be the base oil used in order for the "matter" of the Sacrament to be valid.
If you look at the response to Obj. 4, it confirms my interpretation. St. Thomas is saying that even though olive oil is not found in all parts of the world. It is "enough" that it is possible to send it easily when needed. The reason for this being a non-problem is that the Sacrament of Confirmation is not necessary like the Sacrament of Baptism. Therefore, if people have to wait for this Sacrament because the oil has not arrived, it is no big deal.
Bebedikt's assessment is correct. I'm basically repeating what he says in a slightly more expansive way.
The part that I high-lighted - may I ask, does St. Thomas Aquinas teach this (and if so where) or is this your personal opinion?
The following in the Summa is under the tile: Whether Chrism (oil) is a fitting matter for this sacrament (Confirmation):
Hoc etiam oleum proprie dicitur oleum, et maxime habetur in usu ubi haberi potest=
Moreover, this oil is called oil properly, and is very much in use,
wherever it is to be had.Quilibet autem alius liquor ex similitudine huius oleum nominatur, nec est in usu communi, nisi in supplementum apud eos quibus deest oleum olivarum. Et ideo hoc oleum solum assumitur in usum huius et quorundam aliorum sacramentorum =
However, any other liquid named after the similarity of this oil (meaning a similar oil to Olive Oil) is not in common use except when supplementing among those deficient in olive oil.
This similar oil is not in common use = inferring it is sometimes used.
But is more commonly used as a supplement when Olive Oil is deficient.
The very fact that other similar oils were allowed by the Church supports Pope Pius XII, who teaches that the Church cannot alter the substance instituted by Christ but does have authority over the substance that the Church has mandated (Sacramentum Ordinis, 42)
St. James merely states 'oil' which St. Thomas Aquinas states means the native oil, that is, olive oil. Yet, here we see that similar plant based oils being commonly used as well. Regardless of how they were used, they were used. According to your reasoning, all those early sacraments were invalid.
Reply to objection 4 refers specifically to Confirmation. As it is not as essential as Baptism, one can wait a while for the preferable Olive Oil to be got.
However this reply could not be applied to Extreme Unction and indeed, given the title, it only applied to Confirmation. So what did the Church fathers use when Olive Oil was lacking? Or did they let people die without the Sacrament while waiting for the post?