Most of us here are interested in the best sound quality we can get. While there are definitely flavors in sound and differences in absolute sound quality… if you know the kind of sound you want and do your research, then every time a component of double the price is going to sound significantly better.
What constitutes 80% or one is completely in our heads… or no question the $20 component wins. But, you get what you pay for. The real question is do you want the best sound you can afford or just a really cost effective system. You are toying in the mid-fi vs high-fi realms.
A good used audiophile preamp that you can purchase for around $4K-$5K can be a central hub of an audiophile system for many years or decades. A $2K preamp will sound pretty good… but never give you the highly refined sound of a hi-end preamp, and the solid construction.
Solid state preamps can sound very much like tubed these days… there has been a lot of improvements in solid state. But you end up paying for it. Personally I would only look at tubed preamps. Most can last for many many years without a thought to tube replacement… and the tubes are small and not expensive.
Anyway if you are looking for really good sound, buying stuff that might be “good enough” is going to be very disappointing and cost lots more in the long run as you buy the cost effective stuff and then keep trading up to get better sounding or drop out because none of it was worth it. Each purchase must be carefully chosen to maximize your enjoyment, or probably you will not.