Yes, if the work conditions of Chinese workers gets better, they'll become happiers, but the prices of our favorite gadgets will definitely increase. That's a no-brainer. However, for me, the price doesn't matter. I see a huge human rights issue in regards to the people making the gadgets that they can't even afford in China.
High technology gadgets will not become more expensive, even if Chinese workers get better working conditions. Companies will simply more their factories to other developing countries that have favorable exchange rates and large labor supplies. Someone companies have already started to relocate to Vietnam or Cambodia in order to cut costs.
No, tech gadgets will not become more expensive if Chinese workers become happier, because we can have Chinese people be happy workers and inexpensive goods at the same time. If anything, with a good environment, people will be willing to work harder and will become more loyal to their companies.
Correlations must exist to explain cause and effect. In this case, I do not see a real correlation. Humans become happy for a variety of reasons. I may not be happy about the same thing a peer may be happy about. It really depends on the situation. Happiness is not linked to tech prices.