I think this is hugely reaching, as though some random french craftsman is consciously making an art of his speech. It's just an accent. Accents come and go.
No, it's really not. The spoken French has simplified over time and lost nuances in the process. It also shows if you compare tv news from the fifties and now. The parent remark is not about accent.
It has gained new nuances in the process. I wouldn't call it a simplification, given that foreign speakers often struggle with some of the finer points of slang.
I would not say that nuances were lost. At most, word usage and the way nuances are expressed have changed. People from the 1910s just happen to make use of many words that have fallen out of use for the people living in 2021.
Someone from 1910 would have a hard time understanding all the neologisms that were introduced after two world wars and decolonization until today.
For us from 2021, someone from 1912 uses words that are commonly found in written works from the same period (and after). This is why we feel it sounds like 'art'. Written words live way longer than spoken words.
Even today, common spoken French is very different from common written French.