Aharon's sons why did they die?

Ksav Sofer (Vayikra 10:1): And they offered before G‑d an unauthorized fire which He had not commanded them. Question: The Tanchuma (Achrei Mos #8) says that Aaron’s sons died because they didn’t get married and didn’t have children. Furthermore it says that they walked behind Moshe and Aaron and said, “When are these old men going to die so that we can take over the leadership of the community?” It is necessary to understand this medrash since it does not seem to fit in with the Torah which gives the explicit reason for their death as being punishment for offering an unauthorized fire before G‑d? It is also astounding that these righteous men - who were in fact greater than Moshe and Aaron according to Rashi (10:3) – should transgress G‑d’s command and not fulfill the mitzva of having children and also that they would speak in such an arrogant manner – “when are these old men going to die?” Answer: It appears to me that the reason that they didn’t get married is that they saw that Moshe’s children did not turn out properly as is well known. If Moshe’s sons were not fit then they felt that a lesson could be learned that surely would apply to the masses. They ascribed the failure of Moshe’s children to the fact that Moshe was constantly preoccupied with the problems of the community and therefore he didn’t have the ability to properly supervise his children. (We see a similar judgment of Chazal regarding the children of Shmuel who did not go in his righteous path because he was constantly involved with community problems.) In contrast Aaron’s sons were great tzadikim because Aaron was not so much preoccupied with the community and thus was successfully able to supervise his children. On the other hand Aaron himself never reached Moshe’s spiritual level because his energy was devoted to his family. Being aware of this they decided that the best solution to the inherent contradiction between serving the needs of the community and the needs of the family - was not to get married. They were fully aware that with the death of Moshe and Aaron they would become the leaders of the community. They reasoned that if they had children they would not be able to supervise them properly and they would end up going in the wrong path. Or if they took the path of Aaron and properly supervised their children – then they would not be able to devote the needed time to leading the community. Consequently they decided the best way to serve G‑d and His people was not to get married. We need to add two other aspects from the medrash regarding their following after Moshe and Aaron and saying “When are they going to die?” It doesn’t mean chas v’shalom that they were looking forward to their deaths or that they were discussing between themselves that when they would die they would become the leaders. The medrash means to describe that they were concerned with understanding what Moshe and Aaron lacked. Moshe was very concerned with the needs of the community and therefore he had children who were not good. Aaron who supervised his children did not have so much time for the community and therefore he did not have the merit of serving the masses so much. Therefore Aaron’s sons concluded that they should not get married. In truth they erred in this conclusion. Because “what business did they have with G-d’s secrets.” Their job was not to second guess what G-d wanted. Their job was to fulfill His mitzvos which clearly commanded them to have children. (We find a similar mistaken understanding described in Berachos (10a) concerning King Chezkiyahu. He also didn’t have children because he knew through the power of prophesy that his children would be wicked. However this was a mistake and his father-in-law, the prophet Yeshayahu, was sent to him with the message, ”You will die now in this world and you will not have any portion in the next world because you didn’t have children.” Yeshayahu rejected Chezkiyahu’s justification that his children would be wicked people by saying, (“What business do you have with G-d’s secrets?”). Thus we see that Aaron’s had a strong passion for loving G‑d and His people and therefore they decided that to be successful as leaders and serving G-d it was best not to have children. This in fact was the “unauthorized fire” which they had not received from G-d. They in fact had not been commanded to lead the people in a manner that differed from Moshe – but they were required to fulfill G‑d’s commandments and get married and have children. Thus this mistaken idea was the “unauthorized fire” and it was the reason why they died. So even though their motivation was for the sake of Heaven it was a mistake. This is my explanation and I think it is very correct.