In some groups, you'll never get your turn. As an experiment, I once counted how many half-second (or more) pauses there were in a meeting I had to attend at work. In half an hour (the duration of the meeting), there were none.

On the other hand, I agree with you. I see some people saying "interruption is ok". I disagree. It has to be an exception reserved for keeping the meeting on track. The normal course of things should be that everyone gets their turn to say their bit or to "pass". People who aren't able to wait for their turn or take too long typically will understand if you/the-manager have/has a brief chat with them later (or the person who called for the meeting should bring them back on track).