Let's say you have 49 different colored small marble sized balls and you stir these up in a random way. (Incidentally, the stirring if motor driven requires a program which requires a random selection for the timing of the motor direction durations.) Anyway, doing it manually between picks there is a point where spending say 3 minutes doing it is no different to spending half a day.
Randomness is related to cryptography and for all intents and purposes it can be produced on a computer. If you get seriously involved with this subject you will find especially if you venture into the cryptography part that it is extremely complex and certainly beyond my abilities or inclinations. Your Credit card transactions and on line banking rely heavily on cryptography.
However, at the level of emulating the physical lotto picking machine this can be done but not with the simple algorithm that you see generally published as these produce too many repeats and distortions. In fact I have tested so called true random number generators and for the purposes of producing results similar to lotto machines have found them to be unsuitable.
To summarize, it's a specialized field and while fobbed off by some as being unachievable it can be done to a level that is very useful. The fact that some Lotto Operators use computer picks and this hasn't made any difference to the odds of winning for anyone means it works.
Colin