Incandescent bulbs have a lot of glass and metal and stuff and animals cut themselves on it. Or, stepping aside from your level of reasoning: http://energy.gov/sites/prod/files/2..._lca-pt2_0.pdf
Scroll to the charts and discussion of environmental impacts in Section 7, of filament, CFL, LED 2012, and LED 2017 lamps, across soil, water, and air, from raw materials and manufacturing to disposal and storage.
And for comparisons between lamps: LED simply does better in every category, including hazardous and non-hazardous landfill.For the LED lamp in 2017, the profile is similar to that of the 2012 lamp, however the significance of
energy is diminished due to the fact that this lamp is considerably more efficacious. For this reason, the
other impacts are able to gain a slightly higher proportion of the relative impact for each of the fifteen
categories considered. In this analysis, energy in use represents an average of 78.2% of the impact,
followed by raw materials at 19.3% and manufacturing at 2.3%. The transportation and disposal of the
lamp are negligible, at less than 0.2% each.