Independent labels are roughly 40% of the market and revenue is growing which is only a sign the modern music industry is thriving.

Today indie labels often setup licensing and distribution deals with a major for a portion of the profits. The 1975 for example are on an indie label Dirty Hit with a distribution deal with Universal (Polydor in UK and Interscope in US).

It's similar to the 1980s when most new wave/alternative artists were on indie labels but might have had a distribution deal with a major like The Smiths (Rough Trade) and Depeche Mode (Mute) under Sire (Warner) in the US.

Major labels most likely aren't going to acquire bigger indies such as Beggars Group or Secretly Group, so don't think you will see a return to the 1990s when the underground went mainstream after Island, A&M, Geffen, and Virgin were acquired in the late 80s/early 90s.