I dont see a way how to reduce costs. Increasing of block size would not work. Thats just more space for inscriptions. Making blocks more often is a similar issue but moved from space axis to time axis.

The only way is to change incentives somehow. E.g. make smaller transactions cheaper and make bigger transactions more expensive. Thus, the inscription-like stuff would become more expensive and sustainable and smaller transactions would still find space in blocks.

However the devil is in details and unintended changes we cannot see now. The system is very dynamic and chaotic, i.e. difficult to predict. I am afraid that the best bitcoin is the most stable and predictable one, thus the one with least changes in the protocol.