Protos are kind of an odd unit. They were intended to supplement the Jaguars' 'Mechs and the Jags lack of resources to produce 'Mechs in vast quantities. However, Protos have a very high level of technological sophistication that is required for their design, production, use, and maintenance. Typically, anyone that reaches such a high level of tech, has a wide resource base, it's almost impossible to get to that level without the resource base. The increase in resources almost always proceeds the increase in technology. To get to the point where Protos are viable you pretty much have to follow the Jaguars' path.