The reason the "year of the Linux desktop" hasn't happened yet and open source hasn't conquered the consumer world isn't because of the lack of money. It's because none of the projects have a goal per-se; everyone works in their corner, on their own time, mostly just scratching their own itch. Donating money to them won't solve this problem. There's also a lack of certain skill sets like user experience design, project management, branding, etc.

If the EU wants an open-source conferencing solution they have to do it in-house (whether from scratch or fork an existing solution) and treat it like a business with a clear objective and actual employees (instead of benevolent devs donating their time & effort) including positions which open source projects often deem unnecessary like UI & UX design, and so on.