While I agree with what you said about content disappearing, you've got everything else wrong (in fact, it looks like you're deliberately misstating things). A la carte pricing commoditizes the layers of the TV watching stack, allowing us to shop around and swap out parts we don't care about. Even for people who were taking full advantage of everything their package offered, it's almost assuredly cheaper with a la carte pricing, and for everyone else it certainly is.
Using my own town as an example, Suddenlink is the lone cable provider and their cheapest TV+Internet plan is $98.95 per month for new customers. The same Internet access is $39.95 when purchased separately as a new customer, so we can say that basic cable costs $59 each month, and that's before you include HBO ($+19/mo.), which, I'll note, you conveniently forgot to include in your traditional package example. Broken out that way, it should be obvious just how bad of a deal it actually is, since it's easy to find basic content for less than $59.
With that same $59/mo., we could pick up ALL of these:
1) Access Slim bundle from Playstation Vue for $29.99
2) CBS All Access for $5.99
3) HBO Now for $14.99
4) Amazon Prime for $8.25
All of which is to say, you can stretch your dollars a LOT further by going a la carte, since you'd be gaining HBO content, DVR functionality across all of your devices, and all of the benefits of Amazon Prime (e.g. free two-day shipping, unlimited music streaming, unlimited photo storage, etc.). And that's assuming you actually wanted everything in the basic package to begin with. For our family, we don't care about sports, we don't care about live TV, we don't care about current seasons, and we'd rather binge watch, so Internet+Netflix is more than enough for us.
But even if you're not so extreme, you can still shave dollars in other ways. Don't care about ESPN? Drop to Sling's $25 Blue package. Don't care about seeing CBS live? Save another $6. Don't care about live TV at all? Get Hulu's day-after content and save $22 from what you'd spend on Vue. Don't care about current seasons? Netflix or Amazon gets you old seasons plus a catalog of movies. Hell, you might already have Amazon Prime for the other benefits it provides, so it may be no added cost at all.
And now that our Internet isn't packaged with our content, we can swap the Internet service out. 50Mbps is already 5x more bandwidth than we need for two 1080p streams (which is the most strain we put on our connection), so the moment a cheaper plan is offered by an ISP in our area (fingers crossed), we'll be shaving even more off our bill.