"Anybody agree with me that baby showers (which americans have) are just tacky and quite rude?"
Baby showers are not rude
, that is an odd description of a baby shower. Tacky depends on the people involved. Sometimes there are greedy low class types of persons involved, no more so that in any country though. I have read many threads here about bridal registry lists being included with wedding invitations, those sort are in every country you visit.
I know it is the done thing over there, but it seems to me that if you live in America, you get pregnant and all your friends and family fork out and buy everything for you, including the expensive things like cots, pushchairs and car seats."
Who told you that? Any birthday party, which is kind of what a baby shower is, involves gifts and the extravagance depends on the guest wealth. The ones I have been at, any big gift, like a crib, has been bought by several people going in together. My mil and gm-in-law went together and bought my baby a playpen. My 4 aunts went together and bought a crib mattress. The rest of the presents were outfits, undershirts, receiving blankets type of gifts, and a couple of baby toys.
It is a social gathering, for fun, for the first baby. I do not know why you think it is tacky. Please do not judge everyone based on some people. Any party can be tacky!