You can check the price of everything on line. There's no reason you can't do it with bikes. That's not really the point, as I see it.

Don't take a lot of time from a business when you know you are not going to buy. They have work to do. It's inconsiderate, bad business, and bad manners. If one needs the special skills of some particular
business, don't complain if it costs something. I don't mean you are doing this, I just mean that's more the point as opposed to just price checking.

Are you going to have to pay shipping, or pay to get that on line bike working correctly? Do you need advice to get it fit correctly? That may be the same cost or more than the total of an on line bike purchase. In that case the on line merchant took advantage of you, not the bike shop who wants you to pay to get it assembled.
Is there a full warrantee or a free tune up with the on line bike purchase? You may have to pay for a tune up in the future.

Look at the hidden costs when buying something on line.

Don't tell me you think the price show on the web page is the total cost to you?