I hope some of our experienced professional SR practitioners will add thoughts to my post.
For starters no one enjoys a performance ruined by squealing speaker stacks and to that end what ever it takes to prevent it is better than ignoring the problem. The room proclivities, stage db levels and SR gear limitations and/or miss-management collectively can create feedback.
1) Some venues were not meant to offer SR support: small size rooms with low ceilings are standing wave factories. The necessary remedy of major db filter cuts are sonically never a good idea but will occur with most feedback suppression systems in this type of problem room.
2) Todays pop “hot back line” stage db levels require ultra tight pattern vocal mics that are very difficult to balance with out feedback in the best of venues. When the levels on stage are in excess of 100 dbs the dynamic margins are almost too thin to manage very well.
3) Gear limitations are centered around the front end mic capture and speaker stack delivery systems. Today a simple $1,000. digital CQ20 stage box out performs analog consoles that were 20 times as expensive 30 years ago. However the front and back ends are still primary analog devices, and there is an absolute relationship with budget and performance in these investments. Meyer, KV2, RCFTT are notable high end speaker systems that have highly predictable dispersion patterns that offer clean point source sonic resolution that is much better than less expensive MI gear.
Professional set ups will generally feature a Smaart RTA assessment that will assign no more than 4 small parametric cuts. This is not to say that automated feedback suppression is a bad idea: it is simply making very clear it is not a professional approach to addressing feedback hot spots.
Hugh