I understand what you're saying, but it genuinely works for those that do it. My point about choosing, or targeting if you want to go all 'marketing speak'.
As you say, there are a lot of customers who pay 10/15k for kitchens, they're not the ones you want to aim for. The people who spend 30k plus on kitchens are where you need to look. They are the group who want no hassle, no mess, advice, bespoke features etc. etc. All of which are easy to do, and all of which can be charged at a premium. They are also the group who are going to give you good referrals for people with similar tastes and requirements
It's not all about people spending five figure sums either. Think about the greasy spoon cafe, and how few there are left. Yet coffee shops where people will happily pay a fiver for a coffee or a tea, and the same again for a slice of cake are very busy with trade. They sell a different image, not a different product, and that's the way to sell any trade working on domestics.
We did a job at the tail end of last year putting brick slips on a wall. The slips were cut from reclaimed Victorian bricks (twice the price of new) and pointed with lime mortar, which went onto a wall in a loft room of a new build town house. The customer had never heard of brick slips before I mentioned that they would go with the 'New York loft' style she was after. That was an addition to the work we were doing where I know that mine was the highest quote they had. I sold them a service, an idea, bragging rights with their neighbours because they had something 'different'.
A similar principle applies to quoting for work on old houses. For starters you never ever use the phrase "old house" when talking to the customer. Heritage, period, Victorian (or whatever era) art deco etc. etc. Drop in the 'dying breed' routine about how there are fewer and fewer familiar with the work. You get the idea, basically they are being told without being obvious that they're getting much better value for money by spending more of it.
All the obvious stuff goes along with it, tidy van, not dressing like a tramp, professional quotes, be polite etc. etc.