The BBC spends ~2-3 minutes an hour on trailers - the commercial companies spend ~15-18 minutes on trailers and commercials. Is that "nearly the same"?This is the problem. For a public service broadcaster there is far too much trash TV being produced.
Stuff that should be the exclusive domain of ITV
They've spread themselves far too thin, and now have far too many prima donna presenters who think they're superstars as well.
For every piece of quality content there is 50 trash-tier shows.
And what about the "BBC not having adverts". They do! They spent almost as much time advertising their own shows as the commercial channels spend advertising tat.
Let's face it.. the BBC has become a whale. It's not a lean, mean public service broadcaster. It's got fat on junk food.
One of the main reasons for the BBC trailers is that it allows space to adjust programming and put in things like urgent bulletins or announce changes to the schedule, most commonly obvious on the news channel where the music intro at the end of the hour can be anything from a minute or more, to just something like 10 seconds.
Without some gap in between programs something like a weather forecast running longer due to extreme weather or the news running over due to something important, there is no way to adjust the schedule until gone midnight to get things back on time.
Also what you class as trash programming might be someone else's favourite, whilst what you watch might be considered trash by them
My mother used to hate the "funny head people" stuff (basically any sci fi) but love things like "call the midwife" and "casualty", whilst we hated those and loved the science fiction and crime.
It's also worth noting that the BBC spends less per broadcast minute on TV than any of the commercial companies, which is hardly a sign of it getting "fat on junk food", it's also got far, far higher public service obligations than any other broadcaster in the UK, which tend to eat up a huge portion of it's budget, for example no one else does proper local radio/news outside of the likes of London (most of the "local" commercial stations are pure network with the only "local" content being some weather and possibly a minute or two of news that was usually recorded at the central hub with no ability to respond to what's going on locally*).
*I remember when my local radio station was actually locally based, these days if I travel from one side of the country to the other I get the same "local" presenter doing the news and weather.
It's purely spoken. IIRC the BBC basically invented its written form.
