RPGMemes

It depends on what you define infusion as. Three big theme of magic versus tech isn't that magic stops existing, but that tech radically changes the balance of power in how to use magic. To use a fire wizard as an example, the best use of a fire wizard is different between the medieval era and industrial era.

For the medieval era, the best use of a fire wizard is as magical artillery. Sieges are likely broken as the attacking army has enough fire power from their wizards to burn away defenders in a castle. You likely need these wizards to understand strategy, so they will likely be generals or kings. A fire wizard is going to have a high status in society.

For the industrial era, the best use of a fire wizard is as a replacement for coal. Weapons on the battlefield have replaced the need of fire wizards and some weapons have enough range to be a threat to the wizards, negating their need. Instead, a fire wizard is either used to melt metal or to power a steam engine because they are cheaper than using coal. At best, a fire wizard is going to be at the level of skilled labor in this society as their efforts are best used to be an energy supply.

That shift in power is going to have major ramifications on societies.