Most of these lotteries date from the late 80s/early 90s and there isn't a lot of profit in updating them.
I went to some talks about the database design for the UK lottery where they admitted they didn't think it would be so popular and so hadn't really considered sharding.
They also were surprised that the number weren't uniformly distributed. They assumed numbers would be picked totally randomly while the first win was all numbers that could be birthdays and so there was an unusual number of winners and it took several days to work out how many.
I went to some talks about the database design for the UK lottery where they admitted they didn't think it would be so popular and so hadn't really considered sharding.
They also were surprised that the number weren't uniformly distributed. They assumed numbers would be picked totally randomly while the first win was all numbers that could be birthdays and so there was an unusual number of winners and it took several days to work out how many.