I'm sure there's a real term for what I'm trying to describe. I've found our opinions and values change slowly, over time as we interact and take on new experiences. We think we're more fixed than we really are. Often, that's a good thing - "When the facts change I change my mind what do you do Sir". But, in the same way that only seeing news of one political kilter can subtly reinforce our views, interacting with people who have one set of values has the same impact. Professions tend to filter for values that people care about and that reduces the 'diverse social sphere', it's the real-life version of Facebook filtering news feeds!
Perhaps I should add I'm thinking "in the long term", so comparing working directly in a charity for 10 years versus working as a trader and giving a high percentage of earnings to charity.
It's just I think there's things you can do to counteract this problem, so it's not a decisive point against earning to give.
Yes, lifestyle inflation is a real problem. But it's certainly not universal. Plenty of people maintain high savings rates instead of consuming excess income. The discipline required for early retirement communities isn't very different from that required for earning to give.
That being said, I have found that it helps to maintain a diverse social sphere. The majority of my friends make far less money than me, so it's easy to match my lifestyle to theirs (in fact, a bit better) while having plenty left over for donations.