I think the biggest factor why there are some unknown groups is the length of the festival and the finances of what Disney is paying them.I looked up the 2006 lineup and with the festival being only around 1 1/2 months back then there were 15 acts,this year the festival is a month longer and there are 32 acts,the most ever,there were 26 last year.This year a good amount of groups are only there 2 days,I'm assuming new and mediocre acts only there 2 days filing in the lineup comes cheaper than having more known acts playing 4 days.Several of the regular groups at the festival are still there(Starship,Billy Ocean,Dennis Deyoung,,Air Supply,Boys II Men,Hanson,Big Bad Voodo Daddy),there's some newer groups that have played recently that are pretty solid(Delta Rae,Plain White ts,Sugar Ray)a bunch of mediocre groups and at least for me 5-6 new groups that I have no clue who they are,I know one song from the Hooters but I had no idea who they were.I'm just over 40 and when I first started coming to these shows for both festivals there were a lot of 60s groups with some 70s and 80s and even though most were before my time I really enjoyed the groups they brought in as for the most part were better known than a lot of the groups on the 2017 list,think Beach Boys who we haven't seen in years.It obviously has to do with Disney trying to go for a younger audience while at the same time having to fill out a lineup twice as big as they used to without breaking the bank.I love a lot of the regular groups they bring in as they obviously have a good following and of the new groups there are a couple that I want to see,American Authors,Postmodern Jukebox looks unique,Kenny G cause I've never seen him,as well as Taylor Dayne who's been there before but I haven't seen.