We wouldn’t suggest you avoid making product modification just because of your odd reviews which mentions an old feature, BUT in saying that, we did recommend checking reviews to see if it was a ‘sort after’ addition for just ‘nice to have’. That part is very important.
The customer will buy what the listing details so you’d be fine to change this anytime but to clearly indicate that ‘XXX’ was not included. Brand owners (large and small) make modifications (+/-) all the time, and as Amy’s objective is to reduce current costs for items that are NOT essential and to optimize a market sales opportunity for both products, this is a good idea. But I do agree, due diligence needs to be made on the importance of having or not having a strap