Yes, sort of. That's one way to get peers, but clients support other ways to peers.
So in practice you can get peers from the list of previous peers, PEX (peer exchange), or a tracker for a given torrent.
So in practice once you talk to a few bittorrent peers (of millions) you likely are talking to another DHT peer and can bootstrap. Also given that there's typically millions of peers in the DHT, even brute forcing it by search IPv4 (4 billion addresses) for a few million peers is likely to only involve a few 1000 UDP packets or so.
So in practice you can get peers from the list of previous peers, PEX (peer exchange), or a tracker for a given torrent.
So in practice once you talk to a few bittorrent peers (of millions) you likely are talking to another DHT peer and can bootstrap. Also given that there's typically millions of peers in the DHT, even brute forcing it by search IPv4 (4 billion addresses) for a few million peers is likely to only involve a few 1000 UDP packets or so.