So you want the freedom to lose your freedom, for a short term benefit. Make no mistake: you are not as free to stop using that proprietary software as you might think. Most proprietary software strongly encourage you to stick with them, and make switching difficult. The best examples I have in mind are operating systems and office suites.
The same could be said about slavery: you give up all your freedoms for the ultimate short term benefit: staying alive. Fortunately, we try to eliminate this horrible choice, by abolishing slavery.
Likewise, abolishing proprietary software might be a good idea. Until then boycott is all we have.