The tipping I'm most aware of is in the poorly-paid service
industries like food
serving and some other basic personal services like maids, taxis, gardeners, marine dock
people, etc. The problem, at least here in North America, is that these have become so poorly paid (in general) that tipping is now an essential part of these workers' basic income
If these people were paid a reasonable wage then we wouldn't need to tip them. But it has developed this way for employers to offload the cost of employees directly onto their customers, while maintaining the illusion of lower prices for their product or service
. This model is now ripe in North Americas economy, and is growing.
This is explains why we are seeing the expansion of tipping.