The keyword is "other alternatives" - other technologies (third rail rotary motor?), other operating conditions (shorter train, higher headway?), different requirements, combination of technologies, etc. The report seems almost black and white as its either long LRT or ICTS trains, and it is set up in a way that either options would be very expensive. For instance, they got the cost estimate of the ICTS yard from Vancouver, but due to TTC's different "maintenance practice", the yard would cost 200M more here. AFAIK, Vancouver's yard doesn't even cost 200M. So what's with this special "maintenance practice" that would more than double the cost? And how come a MkII train in Toronto would only hold 70 people while the same train in Vancouver can hold 134? Is it not allowed to have more than 30 standees per vehicle in Toronto? The same applies to LRVs, but to a less degree.
I'm not sure about the LRT options, but comparing the ICTS option, Vancouver's Expo Line have 65% higher capacity and 2.5x longer, but served with only 60% more trains. And yet the maintenance center in Toronto is going to cost 200M more? Why is it so expensive to build anything in Toronto...