Your suggestions wouldn't be effective:
> If you want to change tipping culture, actively apply pressure by never purchasing services if it requires tipping, and following through by writing a letter to the company explaining your decision. Get other people to do it.
Most other people don't care enough about the issue to refrain from patronizing services where tipping is expected, even if they agree, because they only care a little and that would increase costs on them rather than reducing them.
Asking owners nicely doesn't work, because it's this:
> Open a restaurant (or delivery service, or hotel, spa, whatever) and pay the staff a living wage and instruct staff to refuse tips.
As long as customers continue to tip elsewhere, doing this is a competitive disadvantage, because your prices will appear higher since they have to include the cost of paying higher wages, and the perverse risk shifting that imposes costs on workers alleviates them from owners. These industries are highly competitive and minor disadvantages are make or break, so it doesn't work in the absence of a culture shift.
Another unlikely avenue would be a law that bans tipping, but that is difficult to pass because it doesn't benefit the owners and it doesn't benefit the subset of workers who make the most from tips and customers are unlikely to change their vote over this. It's a standard case where the baddies care about something more and it negatively affects a much larger number of ordinary people but only a little, so we get the rules that benefit the baddies.
Which leaves a market-based change driven by customer behavior, i.e. people stop doing it. Which certainly seems like it would work if widely implemented, and people have the selfish incentive to do it, so the only thing preventing it is a harmful preexisting cultural norm that could be eroded through advocacy.