Including the installation fee and $30/mo subsidy (I am assuming this means the price he receives is $30 higher than the one customers pay), my quick math shows it would take a bit over 71 months (almost 6 years) to hit $2.6M in total revenue. However, that assumes literally every customer chooses the $55/month plan, if everyone chose the $79/mo plan, it would take almost 51 months, or a bit over 4 years (obviously the number will be somewhere in between that).
Also, this math assumes no growth whatsoever in homes served or other revenue lines. I assume adding another home will be far cheaper than building out the core network, and the article itself notes other lines of business. To be honest, this doesn't seem like a terrible investment to me. There are certainly better ones in a pure ROI point of view, but for government investments? More of these please!