The singles chart has become pretty meaningless since streaming was included (people inevitably watch stuff before they know whether it's any good) but the album chart is still a fair indicator. Sales remain very meaningful though, unfortunately. If the new album only sells 30,000 in total (UK), it could be 5 years before any follow up. If it sells well (100,000+) a follow up could come as soon as the songs are ready as happened with Ringleader. If you self-release albums on the internet, sales don't matter much but Morrissey won't do that.
A fair indicator of what, exactly?