For perspective, back in 2009 there wasn't even 3G in Russia - the frequencies were all owned by the military, and companies were still trying to wrestle them.
The most interesting part was the scope of the project - the startup nearly went broke not for the need to install 4G equipment, but for the need to build an entire fiber backbone to power that equipment. They invested heavily into building the network that would carry the mobile traffic to the internet al large.
They nearly went broke... And then they became the only service provider giving 4G in a 12 million soul city that knew nothing better than GPRS. It didn't last long, but for a time they more or less had a license to print money.
Last time i checked, that backbone they built is still used by every other provider that built a 3G/4G network since then.
So, yeah. Fiber was the right investment.