Because its a waste of time. Biomass is still the same thing as fossil fuels its carbon based. It generates energy via combustion which produces CO2. A lump of coal and a lump of wood are fundamentally the same stuff, and produce the same waste products. Its even worse because you get half as much energy out of 1kg of wood or plant biomass as you do out of 1kg of coal. So you have to burn twice as much to get the same energy which INCREASES CO2 emissions. If CO2 emissions are your concern then biomass is going at it completely backwards.

Nothing. I heat my house with wood I cut on my land, find in the local dump or from trees blown down by storms that people pay me to haul away. The thing that holds us back is it takes work to use biomass energy, can be dirty and there isn't enough to run everything.

Um, what is holding us back from using all the lighting bolts of electricity, filled with massive amount of energy, to run everything, Or the sun, O yea, that stuff is free.

They only want to give you energy, that you buy from them.

Too much ( relatively ) cheap Oil & Natural Gas flowing around... -I guess. :(

No efficient AND ECONOMICAL way to do so at this time.