We just sailed a 12-day in May. We told our steward that we are low maintenance on day 1. He really started to believe it after a couple of days, as all we wanted were towel swaps once in awhile. We earned some trust.
On disembark day on our way off the ship, he confided to us that they now service more the cabins as before, but only once a day. It wasn't an even swap, because the second service is usually minimal- minor tidying up, maybe a towel animal (remember those? lol). A bunch of first service is a lot of work. Bathroom stuff, linens, etc.
So, yeah, they are a bit over worked. We tip above and beyond, but I really think he valued the low maintenance more than the extra gratuity.