I'm not sure things have ever been any different. There can always be assholes at gigs wherever you play. Not that I've played there but Ronnie Scotts is a prime example. Yes, they will remove an idiot from the audience but there seems to be an ever increasing number of people who don't go for the music, but want to tell their friends that they were there last night.
It's nice of course to be appreciated when you go out to play in public, I'm sure we all want that, but to be respected? you may be disappointed mate. In bars and pubs and clubs, no matter how good you are, you will be just an inconvenience to a small number that want to talk to their friends.
I think there possibly was a time long ago when musicians were thought of as something special as usually, you had to be dedicated, and good in order to survive. These days, with good instruments available cheaply, a willingness of more parents to indulge their children, lessons on You Tube, the platforms to publicise your music and in some cases, simply having the right image, the musical path is open to all.
I gave up the "I'm up here performing for you so you WILL pay attention" outlook long ago. I do it for me these days.