You'll have to ask the ferry companies what the reason is and how you can get your discount now.

There have been since some 50 yrs now always been 2 very competing ferries from STO to FIN (Turku/Abo and Helsinki/Helsingfors), Viking (red ships) and Silja (now Silja Tallink after a merger)-white/blue ships. Both give discounts to passholders-with the EUrail code, but as I found out some time ago, not on all departures. Their prices are now also much more demand-related, just like the cheap budget airlines. On board there is hardly any difference-both are quite luxurious (yes, I´ve used them both). On overnight sailings you now always have to book a berth/cabin. The daytime cruise (to Turku) is very cheap or sometimes even free (except porttax) and has wonderful sights-when the wheather is good.

Why that Eckerö is no more in_you should have asked them-its usually a commercial decision and there is no obligation whatsoever to give it-there are also several rail/train companies who have joined-and said goodbye to the pass-schemes.

As you likely can even think of yourself: its tough times for transportation- high cost of fuel, low demand for 2 yrs due to covid.

From HEL to TLN are at least 4 different ferries-take attention-some are most for cars and land a fair distance out of town!!

Also note that trains in Eestti are very scarce, there is only 1 very bad connection to Riga/LV and further on toward Lietuvo=Lithuania none for now. The BUS is the main form of transport for the very few pax. In these countries the main lines went to the then capital of their world-Mockba (Moscow)- all cancelled now