He most probably did not say that it will result in a lower btc price but in a lower transaction fee. That is not true compared to now since the fees will stay the same as now. Though when we would keep the 1 MB block size limit then this would mean that at one points there are more transactions than the network can put in blocks. That would lead to higher fees paid because the higher a fee the higher the chance to get your transaction confirmed.

That's all.