Technology Connections just did an amazing video discussing the issue of electrifying old houses. He makes a pretty solid argument that 100amp service can be just fine for heavier electrical demands if it’s actively managed. A dumb breaker panel will struggle, but a smart one can allocate the available 100amps as needed (i.e. turn off the water heater for a bit when you run your stove)

https://youtu.be/CVLLNjSLJTQ

Edit: forgot the link