I am going to chime in and say that overall the decline in Sheraton club lounge offerings in many locations have been in serious decline for years now.
IMO it comes with a price tag attached a damaged brand reputation if wanting to pay a premium or remaining Platinum and being upgraded

It's no longer a matter of price and it's certainly no bargain to stay at many a Sheraton. I find myself happy to pay the tab in a competing brand more typically
The problem extends to other SPG properties outside the Sheraton brand as well.The brand standards are indeed better elsewhere
There are some standouts though including Sheraton on the Park in Sydney
Who I assume still does a very nice job