We need to spent money in border to control for Terrorist, Drug smuggler and Criminal. Not for illegally crossing border

The best way to control illegal border crossing is not by spending millions in border -
1. Prison penalty for employer who hires illegal
2. Give prize for those who inform, which company or business or individual hiring illegal.
3. Give prize who inform where illegal is working.
4. Give rights to local police.

Why government does not do this ?