I am joking, of course, but I think you're completely right in that for beginners, a small investment in upgrades (or even just a good solid bike) pays for itself in huge boosts of performance.

Of course, after that, then buying more and better things is just bad for your wallet ;)

After 10+ years on that, I could afford a full suspension bike. I knew what I needed and what parts would fall into the diminishing returns realm. I've been riding it for 5 years and have made some small upgrades (and had to replace a few parts) but I regularly blow the socks off riders on 2-3x more expensive bikes.

My bike does have limitations and if I could afford it I would have maybe 2 more, but as an all around bike and someone who rides all sorts of terrain it gets the job done just fine.

I've also had friends who bought expensive carbon bikes when they're starting out and once they realized that skills are much more important than the bike have regretted spending so much.

I thought about upgrading multiple times because "I had outgrown the bike". An upgrade was $1200.

So, I decided to only upgrade if I could not beat my best time on a specific short trail. Well, I kept going faster and fastee. Untill the tires were the obvious thing holding me back.

I upgraded the tires for $20 (clearance sale) and tested again. Still faster.

Ended up not buying the new $1200 bike.

These days more like 5K to 10K+ unfortunately.

The trick is buying used. But for someone new to cycling, it's easy to get scammed into a bad deal when buying used, so that's not a great solution either.

If you're familiar enough with the components to evaluate them on a used bike, great deals can be had. My first mountain bike (which I still have) was a very expensive model when new (S-Works, which is the Specialized top of the line) that I got for cheap when it was 5-6 years old. It's almost 20 years old now and still everything works perfectly, buttery smooth shifting, etc.

It reminds me of when I bought my first new car, a 2007 VW Rabbit. I knew what I wanted - the four-door non-sport edition, but the dealer asked me if I wanted to test drive the GTI which I didn't know came in a 4-door. I was very tempted but resisted because I knew as soon as I test drove the GTI, the Rabbit would feel sluggish in comparison. The point is, if you start out by test driving something expensive, whether it be a bike or a car, your expectations will rise from zero to very-high and it will taint the well of cheaper options.

It's much more economical to buy a cheaper bike when you have zero expectations, especially if you don't know whether or not you will commit to the sport long-term. You can always sell it and upgrade to a nice $1000+ road bike in the future if you end up loving the sport. I might even recommend going cheaper than I did and buying a used road bike on craigslist for far less than the $400 I spent on a new bike (however cheap $400 is for a new road bike). As others have mentioned here, half the fun of owning a bike is learning how to maintain, repair, and upgrade it over time.

There's a huge range of opinions about what constitutes an acceptable level of quality in a bike. Also, experiences with maintenance will vary due to local conditions. Road salt isn't particularly friendly to bikes, for instance.

There's a serious inflection point at the lower end of the bike market where you get very low-quality kit. I've not bought new for such a long time I'm not sure where it is any more, but ~$400 - $800 is likely around the range for a basic city bike (e.g., "mountain bike" type stance but geared for city streets).

Figure paying half that for a lightly used model, of which there are generally many to choose from for numerous reasons.

mtbr.com is great for reviews and has a deals forum and page. bikeradar, pinkbike and some other sites that will crop up in google are great for reviews too.

For reference I bought a new bmc trailfox tf02 with slx components for 1400 a few years ago and a friend bought a well used but well maintained specialized enduro for 900 last year...i'd say these prices are about as cheap as you should expect to find a good full suspension bike though hardtails can be had cheaper.

There are tons of cheap but not great bikes out there. A good rule of thumb is to not get anything that doesn't have disk brakes and ideally you want something with Shimano hydraulic disk brakes as they are great and easy to maintain. Cheap full suspension is to be approached with extreme caution as it will be heavy and bouncy when you try to pedal it.

My current bike is 10 years old. I bought a $500 hard-tail Marin mountain bike to use for commuting, expecting that it would be able to take some abuse. My wife has a similar vintage bike from the REI house brand at the time (Novara) and it seems of similar quality. I am pretty sure both have Giant frames under their paint. These aluminum frames and disc brakes are a revelation compared to my previous long-term bike which was a lugged-steel Bridgestone with cantilever and cam rim brakes.

I have been almost negligent with maintenance, mainly just oiling the chain and replacing tires and tubes. I don't miss re-packing the bearings and freewheel like my old bike. I am not sure how much that is due to modern tech versus changes in my riding habits. I haven't left the asphalt with the current bike.

I did have to have a wheel re-spoked once after I pounded it in a deep pot-hole with narrow street tires mounted. My Shimano trigger shifters are near the point of needing some kind of major tune-up. I think I would have preferred to keep the simpler indexed levers from the 1990s, as they required a little more operator skill but were less finicky.