“What about women who work in an environment that precludes covering your hair with a hat or tichel or snood? What are they supposed to do?”
My wife’s employer has an absolute rule against wearing headcoverings EXCEPT when required for religious reasons. Most employers in America will be lenient here, especially in the NY area where there are so many Jewish and Muslim women who cover their hair. There may also be some protection under state civil rights law.
My wife has a whole closetful of hats and scarves for a total cost of less than a single human hair wig.
“When did Jewish women wear wigs for the first time?”
While they seem to have been mentioned in the gemara as commenters above have noted, wigs were pretty much unknown in lands were Jews lived for a thousand years and returned in Europe in early modern times as a non-Jewish custom among both men and women. Most of the founding fathers of the United States wore wigs. (George Washington was an exception.) Jews simply followed the non-Jewish customs. With rare exceptions such as British judges, men stopped wearing wigs about 200 years ago.