You can cellar your own wine. Lots of people do it, but cellar conditions matter and it's an expensive hobby. It's nice to not need to know five years in advance what you will feel like drinking tonight. Optionality is worth something.
But yes, with care a hobbyist can do better than how some retail wine is kept.
Edit: The main points are 1) cool (~55F/13C), 2) dark, 3) not too dry (70% humidity is usually recommended. This is to protect the cork), and 4) store on its side, also to protect the cork from drying out. Five years is a long time.
Most retail wines are made to drink now though. If it's on the shelf it's ready.
Not all wines are the same! Some can benefit from aging but not all.
The whole idea of "sealing" wine in a bottle is to keep it and not actually change it. It's a preservation method. However, the bottle is not really completely sealed and the small air gap at the top is not empty either. The cork might allow a tiny amount of air transfer too. The remains of the wine creation process might also leave some reactive components.
When you store wine it seems that a cellar type environment with its stale and earthy air helps - hmmm I wonder why!
Challenge your tastes or whatevs. For example you might find that a really cheap bottle of white chilled to about 5C and fizzed in a Soda Stream makes quite a decent Champagne analogue.
Haha. Rewinding back to my university days, I had picked up what I thought was a very nice bottle of Beaujolais. I put it above my fridge... and fast forward, opened it with my Bride of 20 years. Pure vinegar. I suspect that bottle had just about everything wrong done to it storage wise, outside of freezing solid.
There are very few wines that could be aged , most commercial bottles are good for 1 to 3 years bo matter how well you store them. Even wines from respectable producers are often going to start being broken in 10 years or so. Wine is living thing and the biological and biochemical processes are going to ruin the liquid at some point. Wines that could survive 20, 30 or more years are exception not rule and you need to know which one to pick.
Depends on what your location and budget is. Storing wine outside or at room temperature doesn’t age it the same way a wine cellar in France would. In general you want ~53-57 Fahrenheit and 50-80% humidity depending on what exactly you want to happen.
Unfortunately, simply digging a hole in your back yard only gets it to the average temperature of your area which may be quite different to that hypothetical wine cellar in France.
In the end keeping even a fairly large room at whatever temperature and humidity level you desire isn’t that difficult, assuming you have the space and budget.
I guess what I'm asking is if there's some special storage requirements which can't be met at home?