Given the information you have provided, we cannot say with certainty that it is just poor luck, however that is the most likely scenario. It would indeed be very poor luck, however, people in my presence have failed to have Solar Eclipse events for very long periods. Not playing 8-hours a day for two months as 500 hours would imply, but definitely long periods.
The fact of the matter is that the Solar Eclipse is a random event and thus could fail to happen for an arbitrarily long time after defeating the first mechanical boss (or Plantera in the appropriate versions.) It is described as occurring "rarely". The history indicates that it was even more rare before 188.8.131.52. Although that is a PC version and I am not sure exactly how it maps to the console version.
This very frustration is probably why the 1.3 PC update included the item to force one to occur.
There is always a small possibility that it is a glitch. In which case starting a new world might help; once the appropriate bosses in that new world were defeated. (The Wall of Flesh, The Mechanical Bosses, Plantera). Since you could use your current gear in the new world defeating said bosses quickly should be far easier than it was the first time, but it would still be time consuming.