I have 3 cheap bikes in the basement; hardly used, the youngest of which is more than 10 years old now. A 4th old bike, 21 now, is still in excellent condition - also a Giant as it happens but it wasn't cheap, even in 2000 as it was their top of the line MTB back then. The bikes look good and friends and family who visit and occasionally use them comment upon how corrosion/rust-free they are and how well they ride for trips to the beach locally. I had a cheap fixie bike when I lived in Amsterdam - about 300 euros I think. I really liked it, used it for shopping etc. Cheap can still be ok.
The common theme with all of the aforementioned long-life bikes though is that even collectively they will not have travelled more than 2500 miles in all that time and have lived in garages. Compare that to my 3 current expensive bikes that have collectively done over 27500 miles in the last 2.5 years...the MTB over far harsher terrain, raced too. The road bikes raced, trained hard with in all weather. None of my cheap bikes would have lasted this long with that kind of use and they certainly would not have been as comfortable for that use.
Cheap bikes are fun, good for many use scenarios but for heavy use or racing, lots of fast mileage, the sweet spot is on the expensive side - assuming not buying used, naturally.