The mobile internet infrastructure can sustain the high traffic generated by such outage. There are 4 mobile phone service providers with broadband 4G and very low prices compared to the rest of Europe (Telekom for example offers unlimited traffic for 4G internet at 5 euros / month) so it should be no problem for residents from Timisoara to access the internet.
The ISP's were notified since 2016 to move their infrastructure underground but they ignored to do so.
I think the mobile coverage is better in Romania compared to the rest of Europe. It's hard to find a spot without coverage from at least one cell provider. There are only 3 roads in Romania that have spotty coverage and this is because of the technical difficulties, those roads are deep in the mountains. But also most of the mountain trails are covered. In 2012 there was 600 very small rural communities without coverage and in 2016 only 100. I believe that now everyone has signal at their home from at least one provider.
For example, this is the coverage map from Orange:
https://www.orange.ro/acoperire/harta-acoperire-retea/