Keeping to certain rules because you find them useful and because you like the results, or because your audience likes the results, is what many artists do. Such artists can be creative within the rules they have accepted.
If the situation changes, regarding the economy, or the artist's own satisfaction with the rules, which he might begin to find restrictive or boring or purposeless, then the creative person will change the rules. The less creative person will tend to cling on to the old rules.
Perhaps the Impressionistic and Symbolic painters, and Picasso in particular, are good examples here. As I understand, Picasso's early works were representational and photorealistic. The realisation that photography could do the job much more efficiently was a motivation for him to change his style in a creative manner.
It's interesting to speculate, if the camera with recording capabilities had not evolved, would Picasso have continued to paint in the representational style?
He did all sorts of things during his gig, including ceramics which, apparently, was his gesture to open possession of a 'Picasso' to a general public that he knew would never be able to afford one of his paintings. I suppose it's like a 'thank you', a paying back as it were, to the people whose adoration was beyond their means but, nevertheless, important in creating the mystique. All artists need some of that magica publica if they are to get their heads above the waters of life, never mind above the bleedin' parapet!
As to changing style: why couldn't he just have become bored? If you, as a photographer, spend days a week looking at somebody surrounded by a roll of white Colorama you soon realise that all the troubles and tribulations of the outside 'location' world are worth braving if only to save your sanity. A change is as a good as a holiday, I'm told. And living a successful life in the South of France was not something to knock. Living a poor one would be devastating, if only by the constant under-your-nose presence of the goodies outwith your reach but not of your gaze. A bit like living here, come to think of it, and I have to confess to having had bad moments in my early years on the island looking at those Sunseekers and Rivas I could never own. But you get over it, mainly by realising they don't bring happiness, just more problems in the shape of costs and obligatory crew - it the boat's big enough to make the bother worthwhile in the first place. Truth is, any boat I could afford was always going to be too small to serve its purpose if in my ownership. And considering the scary effects ultraviolet's already had on my skin, maybe just as well I was relatively skint and didn't buy myself more daily exposure. A ski boat is not funny in Med summers, unless in motion (rapid) that fools one into thinking it's cool- UV laughs with you all the way to the clinic.
But anyway, whether Provence or Mallorca, those were different days with diffent people and types; today you get drug barons and the nouveau riche, not writers, poets, artists of worth and the beau monde of yesteryear... all lost with that bloody dirty baby in the tub. Damn the Great Depression!
Rob