Most of those people have daddy paying the bills or live in a damn trailor to afford the car mods.
It has nothing to do with being just a civic or just a Protege.
Its about how much can you really expect from the car and when it just doens't make sense to keep pushing it.
Building a car takes time and money and not many people have either.
Also you have to consider the second car you need to keep project one on jack stands for as long as it takes.
Once you consider I have a $19K car, then add the $5K in mods to get where it is along with the time put into it, then add in the cost of the second car I need to have the ability to work on the MP3, then add in the other $3K needed to make it run even close to say an evo... and you realize how unproductive it is to mod the protege.
Take the MSP as an example. YOu can get it for $17K now, then add the exhuast, clutch, upgraded intercooler, upgraded radiator, upgraded intake, probably even an upgraded turbo, boost guage, fuel guage, wide band, knock sensors, and engine management and sure your out running an evo, but you payed practicly what an evo buyer did and he spend ZERO time in the garage, or tweaking and tuning. Also keep in mind, he as only to spend maybe 1.5K and your a memory at the track again. Also at this point he is still has a far more reliable and drivable car.
You have to keep in mind there is absoluetly nothing on the protege designed to take 250 whp, NOTHING! That adds up to one huge realibilty risk.