American Football evolved from Rugby Union. In the 1920/30's American Football was reviewed due to the number of fatalities - they introduced helmets, or PPE for all you wonderful safety people. It seems it might have helped to reduce short term fatalities but there are now longer term side effects due to helmets clashing etc.
If the UK rugby union teams wish to remain competitive, any changes to the rules, and the way the game is played have to be carried out internationally, or you can quite literally kiss the competitive edge they hold (well, as a southern hemisphere team supporter, I can't say they've been that competitive anyway - what is it 7 world cups to 1 in nearly 30 years?). Unless of course, any safety features introduced enhance the capability of the players. Also, most professional players have been playing the game since 5 or 6, with contact starting at a fairly early age. If the age for when contact training is allowed differs, I know which country I would back. The one whose players have been playing the game for longer.
In the professional era, players are bigger, stronger, fitter quicker and this is due to better training and nutrition (although perhaps certain supplements and steroids whether banned or not make a big difference). The forces experienced during collisions and impacts are likely to be bigger too. That aside, injuries are common to almost all parts of the body, knee injuries fairly frequent. Playing with a broken nose is the done thing.
Would I want my son to play rugby? It's something I've grappled with a lot. He's being playing since he was 20 months (rugby tots) and for a six year old has some good skills. I nearly enrolled him with a local club - but he had also started karate when he was 4, and I've since decided that's a better option. Why? Well, with my H&S hat on, injury in rugby is inevitable. Yes, it could happen in karate, but its non-contact for now. Most rugby players play with some form of injury or other, and it's quite common for players to play with more than one injury. If they didn't, they wouldn't be playing much. Also, whilst he is big for his age, he's not aggressive in any way and I'm not sure he's that into rough and tumble. He tends to shy away from that. He's likely to exceed my height, 1.95m (6ft4 in old money), and with a mum that is nearly 5ft10, I would imagine he is going to be tall. Plus, I've been told I'm built like a proverbial brick ****house, so the kid is going to be big - and if he is athletic enough and chooses to pursue it, could do well in a number of sports.
So after my long diatribe, could rugby be made safer? They are working on it. But major changes could change the game from what it was. This is tradition folks. 150 years odd. People vote with their feet. Rugby is like a modern day Roman gladiators contest. For as long as people enjoy the spectacle, and are willing to pay to watch and marketers can make money by investing in advertising around the game, and teams have money, and players can earn money, it will attract people to play the game. Money aside, many many people play the game simply because they love it. But, excuse the pun, the playing fields have to be levelled on the international stage or UK team, despite best intentions, trying to keep people safe will could fall behind if those safety measures make their players less competitive.
On another note, have we made the products we consume safer? A lot of the manufacturing industry has been exported to other countries with less favourable safety conditions. We've exported the risk to keep the products we love. H&S has a cost. Its might be good business, but only when the playing fields are level can it be truly competitive.