Where is the car now? At a shop? Is it that that this shop is the one suggesting all these parts be replaced and is the car at this point under the control of the shop?
Who is doing the diagnosing?
Can it be driven and diagnosed?
Sounds to me that some one is fishing for work and thus money.
The last "shop" that treated me in such fashion was a chain shop that had frequent turnover of "managers" and employees which seems to be the norm. And after the "associate" explained to me what my car needed in terms of repairs and told me the reasoning was complex and I really did not understand how things worked I pointed out that the number of cars on record that I owned that came through said "shop" requiring alignments after I had gone through rebuilding them that if in their opinion, this one needed them replaced again by the qualified intelegent "asscociate" who I am sure used English as second language and I am not too sure whose reading skills were up to snuff, they could put the car on the ground and I would take it out of there.
And I did.
A couple of years later the second shop I went too that also "had" been doing the same thing, changing staff on a regular basis carefully went through the same explanation on the same type of car and when I pulled the service manual out and pointed at the part and asked to talk to the mechanic, backed off.
The mechanic turned out to be an experianced one who frankly was pretty much following shop procedure on that particular part which generally is no longer adjustable on current model cars basically said.
"I'm sorry, it has been years since I had seen one of these and forgotten you can adjust it"
You need a second opinion I think, and a better diagnosis.
The question sounds like what is the possibility you can actually get one.
To me it is a stretch to have all 4 bearings go out at the same time. It is less of a stretch to have both front one gone, but the car is old enough to be neglected and it could be.
It is a ton of work to get the steering knuckle out, and even more so to get it out with out damaging the lower ball joint. (This from memory, most of them require use of brute force rather than an easy removal procedure. It can be done with brute force too with out damage if you are good at it.) And yes it will need an alignment too and usually does. I guess they are about $60.00 or so now and while pricy are generally needed and worth the expense. AS I am writing I do not remember what it takes to get the lower ball joint out. I have done it a couple of times and it has been more than a few years since I have.
My Saturn seems to hold an alignment pretty well and I have bounced it off curbs at times through not paying attention to what I was doing.