Keep in mind retrofits will keep being popular because they will be able to be retrofitted more than once. Look at how far the quality has come in the last 5 years. Imagine where it will be 5 years from now? We'll be able to go back after 5-8 years and re-sell those retrofit projects with the newer, better LED retrofits.
Integrated LED systems won't be able to offer that (unless they are using a modular design). They are more robust and can do more than the retrofits, but they will be stuck, and you won't be able to change intensities or beam spread like you could with a retrofit.