You can get 1G/1G (or more) symmetric today, if you order a leased line. Expect to pay £350+ per month on a 3 year contract.
Openreach are highly unlikely to make home FTTP symmetric, for several reasons (not related to the underlying technology):
1. They don't want to eat into their high-revenue leased line services.
2. The proportion of customers who care about upload speeds is tiny (albeit vocal). The competition with altnets is primarily on price.
3. It encourages people who do need more upload bandwidth to take a product higher up the range.
Also, it's hard to use download bandwidth excessively - you have to sit there watching all those streams or playing those 100GB games you've been downloading. Users on 1G services don't actually use much more traffic in total, they just complete their downloads faster. However, uploads are easy to saturate 24x7, e.g. if you're running a torrent server and the rest of the world is downloading from you. In essence, limiting the upload speed is a way of providing fair usage limits on an "unlimited" service, and therefore keeping the overall cost down.