While I didn’t keep up with this discussion, the premise is good, don’t waste $ but my interpretation differs in some/many ways;
computers, the real cost difference can be a lot but in my opinion buying a cheeeap basic computer is, depending on how much you dive and where, wasting money. A VD (vacation Diver) who only goes to warm (ish) water and boat dives (with a guide) can probably get by with nothing but an SPG, the are unlikely to ever do enough dives, deep enough to have any risk, they will follow the guide on a 30 to 50 ft 37 to 42 minute dive and surface near the boat get back on to a snack and bottle of water.
Regulators are irrelevant since just about anything can do this profile with good enough performance.
exposure protection is of little relevance too in many of those trips as they aren’t down long enough or deep enough for it to matter.
fins are of little relevance too for the vacation diver.
there is nothing wrong with this “few” dives per year diver, probably 80%+ of people getting certified will be in this group, they support the “in the water” part of the industry.
but once you think you really like diving, enough to go in cold water, to want to do longer dives, to dive in less that great conditions you’ll need better stuff.
sealed first stages, a better reason for those is keeping outside stuff out of you first stage, this is more important with pistons, it takes a long time to wear down the chrome in the ambient chamber but it will happen to the shore diver’s reg.
second stages, better designed ones are far more and easily adjustable, this matters to me and some others, a old very basic design can function and serve perfectly for most, I want more. Buying used saves a bunch of $$ if you have some basic knowledge and sometimes luck.
exposure, you don’t need a $3500 drysuit, not that you don’t want or need a drysuit but a great one can be had for $1k or less.
fins should fit (not easy when you wear size 15 shoes) and move you well through the water, not so stiff that you roll with each kick and not so soft that it’s like riding a bike in first gear on flat ground, there are some really well designed fins available, the best ones are pricy and with newer thought applied, they may look like 60 year old designs but there are improvements. Jut because a fin is popular doesn’t make it work well on your legs! More $ is probably wasted on fins than anything else.
masks, fit first after that different choices like straps, one lens or two, some people like clear (I can only assume they like looking at their own eyes ‘cuz that’s all I can see with a clear skirt) colors are available but fit is foremost.
there are many ways to not waste money, one is not buying crap that won’t serve your needs because its a few $ cheaper. Cheap is good but crap is crap.