There is a lot of variation in what works. People also tend to use a lot of approaches that may not work very well in various situations.
The cold hard fact is it is very rare to get really good sound, and when you do it's generally because a lot of random parameters came together to produce an unexpected gestalt that you probably won't be able to adequately explain. Because of this, performing live is often more about striking a compromise that everyone can accept, rather than achieving perfection.
The person who insists on perfection all the time is typically taking more than his/her fair share. In other words, making it better for one often means making it worse for everyone else. IMHO the priority should be on giving the audience the best possible experience.
Back in the glory days, some bands would run a literal wall of amps. Over recent years, more and more bands seem to be totally abandoning stage amps and using in ear monitors. These two approaches represent the opposite ends of the spectrum, and there are lot's of different approaches in the middle.
My last touring rig was rack based and had a 250W stereo power amp. I had a pair of Eden cabs: D410XLT and D210XLT. I could run either cab or both. Most of the time I ran only the D210XLT. It was placed vertically on top of my 16-space rolling rack with a spare CountryMan Type 85 DI lodged under the front edge of the cab to tilt it back to aim at my ears.
The D210XLT is a pretty efficient cab. With 250W, the calculated SPL is almost 127dB. I used this rig for all sorts of gigs, ranging from private parties for a dozen people, to full-on stadium gigs. Sometimes it wasn't quite enough, but I am not really willing to turn up any louder.
FYI: I wore ER15 or ER20 ear plugs for almost all performances. IMHO these greatly degrade the sound, but my hearing is still relatively good for my age despite a couple of decades of performing.
I like elevating my cab and tilting it to aim at my ears because I want a very clear and coherent sound that cuts through the mayhem on stage. Also I want to be able to monitor effectively with the rig turned down as low as possible, so it fights less with the PA. Some bass players like big fat pillowy lows and hate to hear the highs. My approach will not work for those people.
I would argue that people who like big fat lows tend blow out the house more. By this, I mean in order for them to hear well enough on stage, their rig may overpower the house mix.
Often the audio tech is interested in keeping the stage volume relatively low, so he/she can build a nice mix at a comfortable listening level for the audience. If the stage wash is too loud, the audio tech has two choices: 1. Turn up the mix so he can gain some degree of control over the sound. 2. Pull the sound sources that are too loud completely out of the mix. This second option prioritizes keeping the volume in check over sound quality.
A third option is to try and reinforce the sound. In other words, you try to dial in each channel so the PA merges perfectly with the stage wash. There is an art to doing this well, but in truth, it typically does not work as well as people think. The sound is usually way better if the PA is significantly louder than the stage wash.
Don't make the mistake of assuming that if your sound is only coming from your amp that it will sound good in the house mix. Your sound will tend to become darker and more diffuse as it travels over distance. If you amp is expected to push the room, I would argue that it needs to be adjusted to sound good in the house, and often the necessary changes are opposite of what the bass players wants on stage. Typically either the band leader or audio tech will go out into the house and call changes up to bassist on stage...turn up/turn down, adjust the lows, mids, highs, etc.
This is a really broad subject. There's is lot's more to write, but this post is already probably approaching TLDR territory, so I will stop here.
