[easyThrowaway]

If you adhere to development standards your users aren't locked in to your platform. They could move to better working, more manageable CMSes instead of begrudgingly having to pay someone or, better yet, move to your hosted solution to keep the platform from tripping on its own feet.

Unfortunately that could negatively affect your "Our platform powers 43.4% of all websites" marketing pitch.

[askonomm]

Actually market effects these days make it so that clients themselves demand WordPress, and are unwilling to try any alternative platforms at all. So either I decline the client and make no money or have to use WP.