Making Calls From Landline Through My iMac & Macbook Pro

Question

Hi, being able to make and receive calls from my iPhone 4s through my iMac & Macbook Pro is good, but I (and from what I can see, so many others) also want to be able to make and receive calls from my landline through my iMac, Macbook Pro. Why does Apple not allow you a way of doing this, why can’t they include a way to plug in your home phone through the computer and an app to do this.
I only have so much credit on my mobile and can not ring all numbers from my iPhone without it costing me extra (I know it costs to make calls using this feature anyway), but I have to use my mobile to call 13 & 1300 numbers (as it is already paid for in my mobile credit) but it costs me extra to call these from my home phone, and I have to call 1800 numbers from my home phone as it is only free from landlines which I understand, but when I run out of credit on my mobile I have to use my home phone (Landline), so it renders this feature useless.
I do not understand why they can not include a way of doing this (without VOIP, Skype or anything that is going to cost you more money), like we used to be able to do with older modems, and dial-up etc. I have ADSL2+ and it seems there is no provision to do this by any means, and it also seems the better all the companies try to make technology, the less we are actually able to do with it, and the more backwards it becomes. 
Apple would make an awful lot of people jump for joy if they allowed you a way to do these things. Don’t get me wrong, I love Apple for so many reasons, and I swore I would never go with them, but got sick to death of PC’s, Windows and the troubles associated with them, that I took the plunge. I will NEVER go back to PC or Windows. I do appreciate that Apple is so much better and cheaper in a lot of things, but making things easier for the home and Business user with features they need and want would be so very much appreciated. All I seem to see is what Apple don’t have, and what so many people want, but can’t get, that it is a shame that it all seems to be about the dollar now (Charge more for less) and not customer satisfaction.
PLEASE, if anyone (or Apple) knows of a way to do this without costing more I would love to know, as I have a disability and this would make my (and so many others, even without a disability) lives so much easier. Thanks.

Answer 1

"why can’t they include a way to plug in your home phone through the computer and an app to do this.": Because Apple doesn't control the land line phone. Some providers allow it using their modem, using a app made by the provider/telephone manufacturer, but most don't. Apple simply can't make software for all the phones out there. The problem doesn't come from Apple, it comes from the internet/landline providers.