The "lore" reason is that the many natural disasters and wars has caused a hampering on progress and a loss of knowledge.
Of course wars in real life often cause a dramatic increase in technology due to the arms race that follows, the real reason is that Bethesda decided to be lazy shits and rely on the old "medieval European" fantasy setting rather then do anything clever or creative.
Personally I'd like to see Tamriel evolve technologically for the next game. It doesn't have to go full steam-punk, but I think TES games could bring the already existing man-vs-nature themes to the forefront and have there be an actual conflict between the more fantastical beings and the more technologically advanced townsfolk.
EDIT: Thinking about it more, this could be the perfect place to take the Aldmeri Dominion subplot to the next game. The elves have a mastery of magic while the nords/imperials are more organized and technologically advanced. In addition, it could cause some civil strife due to the empire developing some xenophobia towards other types of -mer due to the war.
Of course wars in real life often cause a dramatic increase in technology due to the arms race that follows, the real reason is that Bethesda decided to be lazy shits and rely on the old "medieval European" fantasy setting rather then do anything clever or creative.
Personally I'd like to see Tamriel evolve technologically for the next game. It doesn't have to go full steam-punk, but I think TES games could bring the already existing man-vs-nature themes to the forefront and have there be an actual conflict between the more fantastical beings and the more technologically advanced townsfolk.
EDIT: Thinking about it more, this could be the perfect place to take the Aldmeri Dominion subplot to the next game. The elves have a mastery of magic while the nords/imperials are more organized and technologically advanced. In addition, it could cause some civil strife due to the empire developing some xenophobia towards other types of -mer due to the war.