Jmurray, Because like everything, Numatic cleaners have been subjected to on-going changes, in the hope it will better the product.
Around 2003, a foot switch was introduced, presumably as it had been seen as inconvenient to try and find the rocker switch in the side of the cleaner, and operate it by hand.
Around 2004, Numatic decided to add a 2-speed motor. There may have been a reason behind it, such as a heading towards the eco-friendly idea, or it could be that it was done because they felt it was what the consumer wanted. I think there is a good chance it may all have been done following customer feedback.
However the foot operated switch was highly problematic as the quality of the switch was poor. The contacts would often burn out, or the locking mechanism would fail. I am not surprised as the same switch was used by other manufacturers and many suffered the same fate if used as a foot switch. They were ok as hand switches but seemed unable to cope with the hefty pressure of a foot. Now as well as this, there is one more point to add. Like a good deal of vacuum cleaners in the past, and probably some today, such was the design of the foot switch button, it was easily caught by the hose when in use, which switched the machine off. The same could happen if the cleaner fell over. This was annoying at best, and at worst put added wear upon the switch.
I don't know much about the mentality of the Numatic company, but they do seem to try and change things for the better, whilst admitting when they got it wrong and changed it back. Hence the two top mounted rocker switches we have seen in recent years. Having tried a foot switch, and having been unable to make it work successfully, they've done the next best thing and made a cleaner with the tried & trusted rocker switches, but fitted them as high up the cleaner as possible, to avoid as much bending down as possible.
There is a fine line between making something a consumer wants, and deciding whether or not they would buy the product regardless. This may have been what was behind the Numatic changes, because whilst I am sure the foot switch was liked by all users, the fact that it no longer has one is probably not going to put anyone off buying a cleaner.
As for the metal tubes, there have been some changes recently, as the design of the suction regulator has changed too. I don't know if Numatic make their own tubes or buy them in. There could be many reasons for changes.
