Rephrasing from my original comment: Because Google worried about a very supply-limited audience (tech workers, including related non-programmers). Most fields, the ones paying their employees far less and with far fewer perks, don't share that restraint. If these other fields had their current crop of (non-unionized) workers get disgusted, the companies would just get different employees.

There's no shortage of companies with various abusive practices that remain in business. Arbitration agreements, micro-management, strict controls over things as simple as bathroom breaks, even riding the line on wage-theft. I'm very glad to see this particular change, but to say "Google's programmers demanded change and got it, why don't you get with it, un-unionized cashiers at S-Mart!" overestimates the influence of those workers.