Not true good sir.
I took a class from an established architecture photographer named Don Cochran (
Don Cochran) and while you are correct it isn't the most lucrative field of photography there is a lot of money in it once you get the right clients. An average architectural photographer is likely to make the same amount as a professional grade portrait photographer (which sucks because its a lot more work) but it can be done to make a living. Of course this all depends on the clients one is capable of getting.
The first thing you want to do is ensure that you have the equipment necessary to pull off a shoot of that scale and a portfolio of images that will catch the clients eye as something they would really like to have created to portray their building.
The next step is to email just about every resort, hotel, or other business based around a building that you can think of, especially newly opening businesses. To make it in architectural photography you have to really want it because people are far less likely to come to you in this field so you'll be doing a lot of reaching out.
Once you are established it may be slightly easier to get client work, especially if you get architects themselves as clients who really like how you've shown off their building. A great way to hold on to architects as clients once youve worked for them is to get educated about architecture and to talk with them about the building in order to portray it in such a way that works with the concept that they had in mind when creating the building. However, even with all of these repeat clients my professor was always telling the class that he was constantly sending out emails to get new clients. (It takes a long time to build an entire building after all, and any business related clients you receive will likely be one time deals as they won't likely need more photographs done unless they make additions to their buildings or interior changes)
I'll see if I can find some class notes or something that might help you out more.