Firstly, tab completion does not need those binaries. Zsh does similar tab completion for git (which uses 150 binaries) and hg (which uses one binary).
Now for TeX, pdfTeX has been around since, well, since the mid 90s. It has been part of the standard TeX distribution for more than 10 years. So for the last 10-15 years, TeX can directly produce PDF.
Similarly, xetex has been around since 2003-04 and luatex since 2007-08. With both of them, using OTF and TTF fonts is as simple as just saying `\setmainfont[Dejavu]` (using the simplefont module in ConTeXt or fontspec package in LaTeX). No need for converting to TFM files or anything.
The reason TeX is built like TeX is because when it started, postscript/pdf did not exist, Type1/TrueType/OpenType fonts did not exist, so TeX had to create its own formats. Over the years TeX has adapted to the new technology: you can easily use UTF-8 input (for text and math), ttf/otf fonts, opentype math fonts, use Lua to write macros, and get PDF output. You are objecting to the fact that TeX works hard to be backward compatible and carries around all the legacy programs so that documents written in 90s still compile easily today. If you don't want them, just don't install them (again this is more of a packing issue than anything else).
Firstly, tab completion does not need those binaries. Zsh does similar tab completion for git (which uses 150 binaries) and hg (which uses one binary).
Now for TeX, pdfTeX has been around since, well, since the mid 90s. It has been part of the standard TeX distribution for more than 10 years. So for the last 10-15 years, TeX can directly produce PDF.
Similarly, xetex has been around since 2003-04 and luatex since 2007-08. With both of them, using OTF and TTF fonts is as simple as just saying `\setmainfont[Dejavu]` (using the simplefont module in ConTeXt or fontspec package in LaTeX). No need for converting to TFM files or anything.
The reason TeX is built like TeX is because when it started, postscript/pdf did not exist, Type1/TrueType/OpenType fonts did not exist, so TeX had to create its own formats. Over the years TeX has adapted to the new technology: you can easily use UTF-8 input (for text and math), ttf/otf fonts, opentype math fonts, use Lua to write macros, and get PDF output. You are objecting to the fact that TeX works hard to be backward compatible and carries around all the legacy programs so that documents written in 90s still compile easily today. If you don't want them, just don't install them (again this is more of a packing issue than anything else).