Ask HN: Feedback on an Open Source business model

Despite the fact I feel quite strongly about using, contributing and writing open source software I've decided to start writing paid for software to be put on the various app store/marketplaces. Most business models I've seen around writing or contributing to open source software tend to be entirely service and support orientated - something I'm not interested in doing. Instead, the model I want to try is releasing software initially paid for proprietary, and then after a set amount of time (say 6-18 months, or when sales go below a threshold) release the code in its entirety under an open source license.

However, I'm unsure of this model for a few reasons. If potential customers are aware of this "approaching open sourcing", will there be a significant portion who'll just wait? If they are not aware of this event, would they feel ripped off or less hesitant to purchase any other software I write in the future? Are there ways of hopefully mitigating both these potential issues - and is there anyone here who has done something like this successfully?