Yes, it seems like since the profit is at 1.77% now and it will be at 1% in the infinite future, the profit has to go down now. Although the profit going down to 1% would be just as possible as the profit going up to 2.54%.
If the site was up 1 BTC on 10 BTC wagered, we'd be at 10% profit. You might think the profit has to go down for the profit to reach 1%, but it doesn't.
If later the site is up 10 BTC on 1000 BTC wagered, the profit is up from the previous 1 BTC and the site is now only up 1%. The profit has increased from 1 BTC to 10 BTC while simultaneously decreasing from 10% to 1%.
See how that works?
Even if the site had won exactly 1% of all wagers after the initial "1 BTC from 10 BTC", then when it was at 1000 BTC wagered (an increase of 990 BTC) the profit would be up 9.9 BTC to 10.9 BTC, an overall profit of just 1.09%, very close to the expected 1%. So even though the house performed just as expected after the initial good luck, the profit still returned pretty much to the 1% level where it should be.
In short the percentage profit isn't expected to fall because the profit falls, but rather because the total wagered increases. There are two ways of making X/Y get smaller: decrease X or increase Y.
