With the way that TV revenues are going and the almost certain increased income from ROW contracts in the next few years (even if the domestic rights stay largely flat) Kroenke may be happy with just maintaining a comfortable upper mid table club. If I was in charge and I didn't give a shit about football and it was only about the money, that is exactly what I would do.
From a pure business perspective it is far riskier to invest the substantial amount necessary to win the PL or CL (and keep Arsenal in that bracket of clubs for a few years in order to benefit from the increased sponsorship deals and worldwide appeal*) than it is to continue as he's doing, especially when the underlying value of the club keeps on increasing.
* Leicester won the league a couple of years back and they didn't receive a massive influx of sponsorship money just because sponsors knew they were unlikely to remain in contention for the coming seasons.
I would be very worried if I was an Arsenal fan. Not because Emery is shit, but because they will probably continue to underinvest in comparison to other top 6 clubs. Unless they get lucky with a Kane or an Alli (I know its not all luck that Spurs got both of these players for £5m in total - but its unusual this happens and you certainly can't rely on it happening year after year) then they won't be truly competitive again. You could argue that that they haven't been truly competitive for years now, but I don't see it changing and probably only getting worse, especially in the light of clubs like Everton and maybe even West Ham showing increased ambition.
I've been saying this for ages. It just doesn't make financial sense to try and win the league if you're in it for the money only. But I think we'll struggle to win occasional cups now and it's tougher to get into Europe. Hopefully Stan will get bored and flog the club at a loss to a sugar daddy who loves footy, as that's our only hope.