Two for me.

For simracing - a set of pedals with a load cell brake. Building muscle memory for the force you push on the brake is so much better than trying to be consistent with the angle of your ankle. The consistency you can achieve with braking is unreal.

Home espresso - a set of accurate scales and a timer. Reducing variables when trying to dial in a new bag of beans or when chasing that perfect cup is so handy. Like the the load cell brakes for sim racing, it allows you to be consistent and just change small things at a time and then stick to what works.

Snowboarding hasn't been mentioned yet.

Anyone who wants to do it somewhat seriously has their own pair of boots, from a reputable brand. Renting, or buying used boots is for rookies.

Also, there's the high-end boards from brands like Burton, Jones and Capita, which will actively try to kill anyone who doesn't know how to ride well.

As a vinyl DJ, I'd say the Wheels of Steel: the legendary Technics SL-1200 direct drive turntable. Though they make newer ones, the vintage ones can go for a grand a piece (if it was in excellent shape) or as little as $500 a piece of they're beaten up. With servicing those things will run forever, they're the gold standard for a reason.

Photography. You'll probably get a variety of answers, but I would venture that a fast, professional level prime (L lenses for us Canon shooters) would be the top vote.

Not the pinnacle, but I am super excited about the Loos tension gauge I just got today. It will help me accurately dial in my sailboat's standing rigging for performance instead of just eyeballing it

Everyone toying with system level stuff on ARM devices should have a cheap but Linux mainline capable board. Like a classic Allwinner A64 based board.

I don't think I have anything that's worthy of the "pinnacle" award, so I'll go with most niche & prized: a hand powered tubular key cutter, the HPC Pocket Cut-up.

It's a mini (roughly measuring tape sized) hand powered all-in-one cutter+jig that can cut tubular key blanks to any code. Any professional would probably get an electric machine instead, so I'm not really sure who needs the pocket version. The small size makes sense for someone who doesn't cut keys for a living, but the price is ~$300 usd. I found it useful for replicating the service key to my apartment laundry machine, which gives access to the hidden start cycle button which normally only presses when you pay via the coin slide. The hand cutter has standard cut depths already set so all you need to do is pick the lock with a cheap impressioning tool and measure the tool once the lock opens to retrieve the key code, which is easily translated from caliper measurements to key code via publicly available lookup tables.

At ~$300 I may have saved some money over just paying since our laundry is $5 per load and I've used the replicated key for over 5 years (back of napkin math says as long as I've done laundry more than once a month I saved money, not a high bar to clear). I could have done it much cheaper by ordering custom keys online, but being able to cut a different code in 10 minutes if I got the measurements wrong proved to be really useful.

As a, primarily mobile developer, my own MacBook Air (MBA) and it's the M2 version.

I do get provided with MacBook Pros (MBP) for work but there's always that advice of separating your own stuff from work stuff. And I wanted to start doing my own stuff and experimenting with beta stuff and the like without messing up the stable dev environment for work. Even though I did consider shelling out for the MBP for more power, I think I valued portability more and the MBA was just way lighter and so far, all the stuff I'm tinkering with are relatively light weight or the M2 just handles it just fine.

Also the act of switching hardware physically gives me a good separation of life/hobby from work, especially not having access to my work code and environment which gives a bit of anxiety, just like the aura of being around work doesn't make me relaxed.

There's no real pinnacle for cycling as there are too many disciplines and brands, but what was eye opening for a beginner was the price.

It's often noted that the price to performance ratio just about levels out at $3,500 for a bike (top end carbon frame and wheels with a 105 groupset for example); anything above that is really for people being paid to race. That doesn't stop people with money burning a hole in their pocket from spending 5-12k on a bike thinking the 60 seconds it will shave over an hour long ride is somehow worth it.

Throw in shoes, helmet, bib shorts/shirt ($300 each) and you're looking at one expensive hobby.

Meanwhile most beginners are out there looking for a sub $1k bike wondering why there's nothing available.

I have an old Miata I enjoy throwing money at. For Miata enthusiasts, it's absolutely owning an OEM hard top.

Might well be this one:
Repurposing an Accom Axial Control Panel
as it combines my previous career in TV, my lifelong interest in programming, my nostalgic tendencies, and my sheer love of buttons galore!
(Work in progress, full write-up is here.)