Why Do We Use Preamps?

I'm a little confused about the concept of the pre-amp. Wouldn't the most faithful reproduction of the source material involve as few steps as possible?

I do understand that some prefer the richness and coloration provided by this or that component, but for a sound that is very high in fidelity to the original sound why doesn't it make more sense to just let your amplifier do the work, with a passive preamp to adjust the volume?

In my opinion the advantages to a seperate pre-amp vs. intergrated or receiver is, better quality of sound.
This is acheived by seperate power supplies doing one task.
In a receiver or intergrated you would have a power supply
powering amplifier section along with the pre amp. And in a receiver the tuner or processing circuitry. All these various items can produce their own noise and infect the sound path. Regardless of how much the manufacture isolates the different circuitry I think it is impossible to completely isolate within a single box using a single power supply. The other reason that I like the seperates is that I can mix and match with different brands, models, SS/Tube etc. I provides much more flexability to any system. In my case I use Audio Research Tube pre amp with McIntosh SS amps. I can use my Pre-Pro by utilizing the unity gain in the pre amp. This virtually gives me one system that is two, one HT and 2 channel. I guess another example can be the use of CD transport with a DAC vs. single box CDPs. I don't use a seperate dac with mine but it has advantages that some prefer. Again a good transport can sound quite differently with various DACs. So one can tailor the sound to please his/her ears. We are all different and the more flexabilty we have in a system the better the odds of conquest in our search for the Audio Grail. These are all of course my opinions and other may add to or disagree. One last note is, that I wrote this today and it is not in the archives..yet. Sometimes the same question gets asked but different answers pop in as not everyone reads each thread. The beauty of these forums is there are no rules against asking.
1. to match impedances between source and power amplifier
2. to control the volume between source and power amplifier

I have gone both the passive and the active route. In theory, your are correct that a passive should give greater purity and transparency. And I do hear that with a passive, but I also think it comes at a cost.

The music loses some oomph, weight, drive and robustness. It can get bleached and thin and somewhat threadbare compared to an active. Personally, I prefer active cause I think it makes the music sound more real and alive.

And please don't say I got these results because I did the passive thing wrong. I followed all the rules: short low capacitance IC, impedance matching, amp highly sensitive on the input, gutsy source output, etc.

Others may hear differently and prefer differently. I'm sure anyone can hear the active vs. passive differences. Then it just comes down to subjective preference. Just use your own ears and decide for yourself.
So if the goal is to add more depth and clarity to the sound, would it then serve almost the same purpose as a tube buffer, or maybe even a separate full-sized amp with gain control that you use further up the chain? Could you daisy-chain 2 or 3 pre-amps together?