No flooring is pretty standard unless offered as an incentive in poor market conditions - which obviously isn't the case. I was stuck with Barratt's (hideous) choice of carpet and linoleum in my last place and resented it for years.
That said, the prices you've quoted strike me as high. We paid Bloor Homes £2,600 for granite worktops in the kitchen which included an upgrade to a stainless steel undermounted sink, and £2,500 to tile the floor of our kitchen diner and utility in 2017. The advantage of having the builder do kitchen floors is that the tiles are properly installed under the cabinets right up to the wall and to the skirting boards elsewhere. It's not as easy to do after the skirting boards have been fixed, cupboards and appliances have been installed and so on.
The work is then also the builder's responsibility for snagging etc, and if there is any damage to them caused by, for example, reinstalling integrated appliances or refitting kickboards (which you'd have to remove to get your own tiles under.) For us this outweighed any minimal savings we could get by doing it ourselves, but your prices are considerably higher.
It also became apparent that because we spent a lot on upgrades throughout the house, it got considerably more attention from site and regional managers. Our nearly-finished house was shown to Mr Bloor himself when he made a visit, so absolutely everything was given an extra once-over!
Our builder offered Symphony kitchens as part of the package although we paid to upgrade to premium Shaker doors for £1,750, which then included three drawers in one of the cupboards. When we saw the paucity of clever storage ideas, the poor standard appliances, the plastic sink, and the shitty laminated counters in the standard kitchen we originally thought we'd have to gut the entire brand new kitchen. It was only when we really thought about it that upgrading the counters, appliances and cupboards gave us about 90% of what we wanted, at a quarter of the cost of a new kitchen. We still don't have fancy pull-out baskets and larder units, but we can live with it.