Machine Bearings (Grumble Type thread)

Why do manufacturers put the "Metal Sheilded" type bearings in their machines?..I have just spent a couple of hours replacing all the bearings in My Clark Sanding Machine after a bearing collapsed...When I stripped it down I found that every bearing was dodgy (mostly clogged up with very fine dust), so I replaced them all with the "Double Sheilded Type" (The ones with the rubber outer seal).....I had to do the same with my SIP 14" Bandsaw a few Months ago...These bearings are not very expensive and you can buy them on E-bay in sets of 10...so why don't they fit them in the first place?????....I have a UK built 60 year old Cast iron sander I restored a while back, and the bearings in that one are completely sealed with steel cover plates with heavy duty grease packed inside.. and I'm convinced that one will run for another 60 years without problems.

The same reason we have once respected companies turning out plywood crap instruments that will eventually end up in a land fill. The bottom line is profit, and if it breaks down even better, throw it away and buy another one. It's a sickness and our planet will eventually offer up a cure.

It's hard to believe that some manufacturers of machinery will use anything but a top quality sealed bearing. When you buy equipment, that should be a #1 priority question.