Using lots of time, attention, and money make for the best systems. We are all budget bound on one or more of these. So if financially bound, then invest more heavily in the others. What your time is worth is both a function of how much money you make per hour by working and the enthusiasm and available time you have to pursue high end audio. But time and attention are also limited commodities and dependent on your values.
As far as percentages… some folks have little ability to influence the room, many cannot. Often folks have a much larger ability to impact the financial investment they make.
As far as the price of components… yes, price in itself does not take into account your tastes, synergy with your system and venue, and may not perfectly represent sound quality. On the other hand it is the one common characteristic shared across all components and the meaning which is understood by all. Certainly, by itself it can only be a very rough guide. But for most, it is a good starting place. Also, most of us start with a budget. If you research, find best of class that matches your tastes beyond simple price you will be making pretty good decisions.
Then finally there is a question of how efficient is the market? What is the relationship between price and performance? This is particularly true once we get above budget gear. If you understand sound quality and are able to separate different house sounds, in general the sound quality rises with price. Much higher design times, higher quality parts all result in better sounding equipment… lower noise floors, more dynamics, higher reliability. This relationship is often obfuscated by the different house sounds… McIntosh produced extremely good sounding equipment… but I do not like their sound… so I could easily label them over priced. For me, same with Wilson. I don’t, because I know better and I can hear what they are trying to achieve. Also, ones individual venue and your other existing components highly influence the sound you get… not necessarily a reflection of the quality… or cost for that matter of the component you put in it.
Overall, however, I have followed dozens of high end audio companies over decades and compared between them. And with the caveats above… price of components is an important shared parameter across all audio that is very useful and largely reflects the sound quality of the component. Of course there are some exceptions… but they tend not to last long, because they are weeded out of the market by folks like us.