Definitely Podio will not be discontinued, we have over 500.000 businesses worldwide depending on our solution.
This summer and fall we will look into building a more robust CRM/PM solution to give you deeper integration with email from Podio. So yes, we will continue to develop more business critical features for Podio.
You're also correct Gantt Chart is currently the top requested feature in the Forum however please note this is only because we already managed to implement the top requested features from the past (2 months ago the most requested features were a customisable badge layout and the option to filter relationship fields, which was introduced this spring).
Hope this helps!
//Sara - Podio