Re: "The... Maemo operating system failed to take off"
Maemo/Meego also suffered from the "partnership" with Intel. Intel got involved, because they wanted desperately to get into the mobile platform market.
At the time, Texas Instruments, owned most of the non-bottom of the market with their OMAP platform/SoC. Those were the days when Intel wanted to get x86 mobile to complete with ever-growing ARM.
Aside: if I understand correctly, OMAP was created for Nokia by TI, because Nokia needed a standard, more integrated platform for cheaper and more reliable phones and to more easily spin out new design at multiple price/performance points.
So Intel and Nokia parted ways and Maemo become MeeGo. And, in the fullness of time, of the grudge release of the Noke N9, MeeGo went open source and SailishOS grew from the ashes of that.
Maemo/MeeGo, apart from a much more modern gesture-based UI, also addressed the painful C++-ish programming model Symbian had.
Nokia had bought Trolltech to get Qt and, under Nokia's stewardship QML came to be. A lot of the mode moden Symbian apps were written with Qt/QML. There was even a Python runtime. Qt/QML was the preferred development programming environment for both modern Symbian and the Maemo/MeeGo/SailfishOS (and even for Ubuntu Touch with Mir/Unity and KDE). So there definitely was a software development path forward from Symbian.
Aside: Symbian Anna/Belle got pretty close to the then-current Android experience and might have been able to tide them over during the switch to Maemon/MeeGo. Save for Elop's "Burning Platform" memo which essentially Osborne'd there entire product line
Aside: Symbian was also (successfully) kept out of the US market by the mobile operators. They crapped themselves when they realised Symbian supported VoIP natively. That could cannibalise their voice revenue streams. It also supported Bluetooth tethering which allowed customers to use their phones as mobile data gateways. Wifi hotspots became the stock workaround for that operator block.